Re: Rietveld ESD calc fortran code typo?

[Matthew Rowles]

Thanks a lot for that Jonathon.

The code is helping me understand the algorithm, in particular the
implementation of the double sum.

Currently in the process of reproducing it in python to get around my
essentially complete lack of knowledge in fortran so I can properly
understand it.

On Thu, 16 May 2024 at 22:44, Jonathan WRIGHT  wrote:

> Dear Matthew
>
> That fortran snippet was corrected in Appendix 1 of Andreev's paper here:
>
> https://doi.org/10.1107/S002188989300891X
>
> It is a shame that implicit none was not part of fortran 77. The google
> search
> resul leading me to that was:
>
>
> https://www.researchgate.net/publication/359342753_Program_RietESD_for_correction_of_estimated_standard_deviations_obtained_in_Rietveld-refinement_programs
>
> https://www.iucr.org/resources/other-directories/software/rietesd
>
> Presumably similar things are computed as SCOR in fullprof output list
> files
> (Serial CORelation). There is some discussion in Hill and Madsen:
>
> https://doi.org/10.1107/S0021889886090076
>
> ... who give the citations for Pawley 1980 and Scott 1983 to locate the
> origins
> of those estimates.
>
> Best regards,
>
> Jon
>
>
>
> On 14/05/2024 10:56, Matthew Rowles wrote:
> > Hi all
> >
> > Just been reading Berar & Lelann (J Appl Cryst 24:1-5).
> >
> > In the paper's appendix, there is some Fortran code implementing their
> ESD
> > multiplier calculation.
> > This code was added to the end of the CHISQ subroutine in DBW3.2
> >
> > I'm interested in line 10:
> > COREL = (DEL**2/Y(I)) + CD
> >
> > Should CD be XD? Is this a typo?
> >
> > If not, does anyone know what CD represents?
> >
> > image.png
> >
> >
> > Thanks
> >
> >
> > Matthew
> >
> >
> > ++
> > Please do NOT attach files to the whole list
> 
> > Send commands to  eg: HELP as the subject with no body
> text
> > The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> > ++
> >
> ++
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> ++
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Pharma samples: prep and data collection

[Matthew Rowles]

Hi all

Are there any publications\guides on the specimen prep and data
collection regimes for pharmaceutical samples? Specifically for
quantitative phase analysis and phase ID.

I know of the ICDD pharma round robin (Powder Diffr., Vol. 25, No. 1, March
2010).

I'm a neophyte in this area, and am looking to avoid major pitfalls


Matthew
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Rietveld ESD calc fortran code typo?

[Matthew Rowles]

Hi all

Just been reading Berar & Lelann (J Appl Cryst 24:1-5).

In the paper's appendix, there is some Fortran code implementing their ESD
multiplier calculation.
This code was added to the end of the CHISQ subroutine in DBW3.2

I'm interested in line 10:
   COREL = (DEL**2/Y(I)) + CD

Should CD be XD? Is this a typo?

If not, does anyone know what CD represents?

[image: image.png]


Thanks


Matthew
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Re: Legendre polynomial coefficient

[Matthew Rowles]

Hi Francois

Reflection mode at a synchrotron? Does that mean you have the beam coming
in at a fixed angle with respect to the specimen, and then collecting all
the angles?

Because of the change in specimen volume with angle, you need to modify the
calculated intensities, as most (all?) Rietveld programs assume constant
volume.

Have a look at a previous paper of mine

https://espace.curtin.edu.au/handle/20.500.11937/50104

and in particular, §2.1 Flat-plate asymmetric reflection.

Hope it all makes sense


Matthew








On Wed, 27 Mar 2024 at 22:24, francois Goutenoire <
francois.gouteno...@univ-lemans.fr> wrote:

> Dear Rietveld users
>
> I have some data collected on a synchrotron line on reflection mode.
>
> The sample is an ancient steel (Fe alpha + Fe3C). The aim is to analyzed
> Fe/Fe3C in order to get the carbon content.
>
> The total scattering volume is obviously not constant with 2 theta.
>
> We can observe an increase of the background and the Rietveld refinement
> is not possible, but the Le Bail fit is good (see on the link).
>
> In order to get a good Rietveld refinement, I would like to modified the
> data (Sorry !! I known is not acceptable ! Joke).
>
> The idea is to use the background to modified the intensities, in order to
> get a flat background.
>
> I would like to use the Legendre polynomials coefficients to do this
> correction.
>
> Does someone know how to to that ?
>
> Link for the images https://perso.univ-lemans.fr/~fgouten/Legendre
>
> Best wishes, francois
>
> --
> *
> Pr. Francois GOUTENOIRE
> e-mail: francois.gouteno...@univ-lemans.fr
> Tel: 02.43.83.33.54
> FAX: 02.43.83.35.06
> Institut des Molécules et des Matériaux du Mans
> IMMM - UMR CNRS 6283
> Elaboration et Caracterisation des Composés Cristalisés (E3C)
> Université du Maine - Avenue Olivier Messiaen
> F-72085 Le Mans Cedex 9
> FRANCE
> *
> Formation Rietveld 
> CNRShttps://cnrsformation.cnrs.fr/diffraction-des-rayons-x-sur-materiaux-polycristallins?axe=135
> Formation EDX CNRShttps://cnrsformation.cnrs.fr/fluorescence-x-edx?axe=135
> Formation SAXS et Réflectivités pour couches minces et matériaux 
> nanostructurés.https://cnrsformation.cnrs.fr/caracterisation-des-materiaux-nanostructures-par-diffusion-des-rayons-x?axe=135
> Bibliographiehttps://scholar.google.fr/citations?hl=fr=qC-lmN4J_op=list_works=1=titlehttps://orcid.org/-0001-5339-3002
>
> ++
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> ++
>
>
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Re: NIST-676a

[Matthew Rowles]

Are there any (Australian??) distributors/suppliers for CR1, or is it a
case of contact Baikowski direct?

Matthew

On Wed, 15 Nov 2023 at 16:55, Reinhard Kleeberg <
kleeb...@mineral.tu-freiberg.de> wrote:

> If CR1 is added as internal standard (20 mass%) to rock samples prior
> to McCrone milling and flat powder samples for Bragg-Brentano are
> carefully prepared, we did not observe severe preferred orientation
> for the corundum, maybe as the powder is fine enough
> (particles/aggregates ~ 1 µm before milling) to be randomly
> distributed in the mixture within the gaps between the coarser mineral
> grains.
> But as Jim mentioned, the profile shape of CR1 is suboptimal, we need
> a bimodal crystallite size distribution model to fit. Anyway, for
> routine QPA the material is working.
> Best regards
>
> Reinhard
>
> Zitat von Daniel Chateigner 20210513 :
>
> > and not textured ?
> >
> > Le 14/11/2023 à 12:56, Reinhard Kleeberg a écrit :
> >> Hi Jim,
> >> great news, would be good to have a corundum what can be modelled
> >> with an easier profile shape model.
> >> Best regards
> >>
> >> Reinhard
> >>
> >> Zitat von "Cline, James P. Dr. (Fed)" :
> >>
> >>> Hi all,
> >>>
> >>> SRM 676a consisted of Baikowski CR1.  This material is of a
> >>> non-ideal crystallite size distribution: quite broad with tales to
> >>> large crystallites.  SRM 676b was custom made for us by Baikowski
> >>> with a more uniform crystallite size distribution in the 200 nm
> >>> region.  We are working on the certification, rather complex, see:
> >>> doi:10.1107/S0108767311014565 .  It seems that modern beamlines
> >>> don't favor the large specimen size needed for our experiments.
> >>> We have good data from one source, we are looking for some from
> >>> another as we like to see results from more one machine.
> >>>
> >>> Jim
> >>>
> >>>
> >>> James P. Cline
> >>> Materials Measurement Science Division
> >>> National Institute of Standards and Technology
> >>> 100 Bureau Dr. stop 8370 [ B113 / Bldg 217 ]
> >>> Gaithersburg, MD 20899-8523USA
> >>> james.cl...@nist.gov
> >>> https://www.nist.gov/people/james-p-cline (301) 975 5793
> >>>
> >>> -Original Message-
> >>> From: rietveld_l-requ...@ill.fr  On
> >>> Behalf Of Reinhard Kleeberg
> >>> Sent: Monday, November 13, 2023 1:51 AM
> >>> To: rietveld_l@ill.fr
> >>> Subject: Re: NIST-676a
> >>>
> >>> We are using Baikowski CR1
> >>> https://www.baikowski.com/en/serie/cr/ Not certified but maybe
> >>> identical with SRM676a. Scale factors and cell parameters found to
> >>> be within the errors. Profile shape shows similar features (also
> >>> not an ideal material).
> >>> Best regards
> >>> Reinhard
> >>>
> >>>
> >>> Zitat von Matthew Rowles :
> >>>
> >>>> Hi Matej
> >>>>
> >>>> You can try IMS135 - high purity alumina.
> >>>>
> >>>> https://imst/
> >>>> andards.com.au%2Fproducts%2F=05%7C01%7Cjames.cline%40nist.gov
> %7C2
> >>>> d945a33db074232a69808dbe414ca9a%7C2ab5d82fd8fa4797a93e054655c61dec%7C1
> >>>> %7C0%7C638354550207433666%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAi
> >>>> LCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C=r
> >>>> MK%2BzDuAMv2q7U6fCpu38mzuqIrTdCiQfNDPSmB%2BQZk%3D=0
> >>>>
> >>>> It was certified against some SRM676a we already had in the lab.
> >>>>
> >>>>
> >>>> Matthew
> >>>>
> >>>>
> >>>>
> >>>>
> >>>> On Sun, 12 Nov 2023 at 22:42, Matej Dolenec  wrote:
> >>>>
> >>>>> Dear all,
> >>>>>
> >>>>> I am trying to buy NIST-676a but unfortunately unsuccessful ... I was
> >>>>> trying to find it on NIST, ALDRICH and other sites but the standard
> >>>>> is out of stock. Does anybody has any information if this standard
> >>>>> will be available soon and where? If not, which standard should I use
> >>>>> instead of NIST-676a? I was using this standard for amorphous
> >>>>> phase identification.
> >>>>>
> >>>>> Re

Re: Misconduct

[Matthew Rowles]

I see the core contribution of the Rietveld method as the point-wise
calculation of a powder pattern. This then enables the refinement of the
parameters.

Yes, attributing QPA to Rietveld is incorrect; that is mainly due to
Hill/Howard and Bish/Howard - I try to make it a point to differentiate
this.

calling PDF refinements Rietveld refinements is just plain wrong (afaik),
unless you actually are moving crystallographic parameters around, in which
case, the nomenclature gets fuzzy..

On Sat, 13 Jan 2024 at 14:39, Alan W Hewat 
wrote:

> The core of Rietveld refinement is REFINING the crystallographic
> parameters to fit the pattern. That was the great innovation. Is that done
> here ? To calculate various patterns to refine phase composition you
> necessarily need models of the crystal structures. But all refinements of
> powder patterns are not Rietveld Refinement. Quantitative analysis of
> powder samples is an important technique, and to attribute that to Rietveld
> is wrong. Same goes for Pair Distribution Function analysis. Calling
> everything "Rietveld Refinement" is not helpful, and actually hides the
> fundamental contribution of this technique to crystallography.
>
> 
> Dr Alan Hewat, NeutronOptics
> Grenoble, FRANCE (from phone)
> alan.he...@neutronoptics.com
> +33.476984168 VAT:FR79499450856
> http://NeutronOptics.com/hewat
> _______
>
>
> On Sat, 13 Jan 2024, 07:00 Matthew Rowles,  wrote:
>
>> Hard disagree here.
>>
>> You're using crystallographic parameters to calculate the (intensities
>> and positions of the) pattern.
>>
>> To me, that's the core of Rietveld refinement.
>>
>> You need to apply a peak shape model. Why not apply a model from which
>> you can extract crystallite parameters?
>>
>> QPA can then be done on the output of a refinement, eg application of the
>> internal standard method using the Hill /Howard algorithm.
>>
>> Its still a Rietveld refinement, I'm not just fitting peaks willy nilly;
>> they're constrained by a crystal model.
>>
>>
>> Matthew
>>
>> On Sat, 13 Jan 2024, 01:48 Alan W Hewat, 
>> wrote:
>>
>>> Apart from the record number of atoms, phases, parameters, citations etc
>>> used to describe just 3 broad peaks, I object to this kind of refinement
>>> being called "Rietveld refinement". Luca called it "Rietveld-like" in MAUD,
>>> which was used here, but even that is wrong. The term "Rietveld refinement"
>>> should be restricted to the refinement of crystallographic parameters -
>>> cell dimensions, atom coordinates etc. and not applied to quantitative
>>> analysis of phases, particle size etc. Fitting peaks in powder patterns was
>>> done before Rietveld, who must be turning in his grave to see his name
>>> associated with this kind of thing.
>>>
>>> 
>>> Dr Alan Hewat, NeutronOptics
>>> Grenoble, FRANCE (from phone)
>>> alan.he...@neutronoptics.com
>>> +33.476984168 VAT:FR79499450856
>>> http://NeutronOptics.com/hewat
>>> ___
>>>
>>>
>>> On Fri, 12 Jan 2024, 12:57 Le Bail Armel, 
>>> wrote:
>>>
>>>> Hi,
>>>>
>>>> A good candidate for the "worst Rietveld refinement of the year" award :
>>>>
>>>> https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06
>>>>
>>>> Even the difference pattern is totally fabricated.
>>>>
>>>> Best
>>>>
>>>> Armel
>>>> ++
>>>> Please do NOT attach files to the whole list
>>>> 
>>>> Send commands to  eg: HELP as the subject with no
>>>> body text
>>>> The Rietveld_L list archive is on
>>>> http://www.mail-archive.com/rietveld_l@ill.fr/
>>>> ++
>>>>
>>>> ++
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>>> 
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>>> text
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>>> ++
>>>
>>>
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Re: Misconduct

[Matthew Rowles]

Hard disagree here.

You're using crystallographic parameters to calculate the (intensities and
positions of the) pattern.

To me, that's the core of Rietveld refinement.

You need to apply a peak shape model. Why not apply a model from which you
can extract crystallite parameters?

QPA can then be done on the output of a refinement, eg application of the
internal standard method using the Hill /Howard algorithm.

Its still a Rietveld refinement, I'm not just fitting peaks willy nilly;
they're constrained by a crystal model.


Matthew

On Sat, 13 Jan 2024, 01:48 Alan W Hewat, 
wrote:

> Apart from the record number of atoms, phases, parameters, citations etc
> used to describe just 3 broad peaks, I object to this kind of refinement
> being called "Rietveld refinement". Luca called it "Rietveld-like" in MAUD,
> which was used here, but even that is wrong. The term "Rietveld refinement"
> should be restricted to the refinement of crystallographic parameters -
> cell dimensions, atom coordinates etc. and not applied to quantitative
> analysis of phases, particle size etc. Fitting peaks in powder patterns was
> done before Rietveld, who must be turning in his grave to see his name
> associated with this kind of thing.
>
> 
> Dr Alan Hewat, NeutronOptics
> Grenoble, FRANCE (from phone)
> alan.he...@neutronoptics.com
> +33.476984168 VAT:FR79499450856
> http://NeutronOptics.com/hewat
> ___
>
>
> On Fri, 12 Jan 2024, 12:57 Le Bail Armel,  wrote:
>
>> Hi,
>>
>> A good candidate for the "worst Rietveld refinement of the year" award :
>>
>> https://pubpeer.com/publications/12069A6AD9D5D34F26031F34705D06
>>
>> Even the difference pattern is totally fabricated.
>>
>> Best
>>
>> Armel
>> ++
>> Please do NOT attach files to the whole list > >
>> Send commands to  eg: HELP as the subject with no body
>> text
>> The Rietveld_L list archive is on
>> http://www.mail-archive.com/rietveld_l@ill.fr/
>> ++
>>
>> ++
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> ++
>
>
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Re: Excluding phases from weight percent calculation

[Matthew Rowles]

Hi Claire

It sounds like you're using the Hill/Howard algorithm for quantification.

You just need to not put the details of the SiO2 phase you're using into
the summation.

This is equivalent to removing the ~90% attributed to the capillary, and
renormalising to 100%

Matthew



On Tue, 14 Nov 2023 at 01:36, Claire Emily Boronski <
claire.boron...@colorado.edu> wrote:

> Hi All,
>
>
>
> I am trying to exclude the glass capillary from the weight percent
> calculations in my Rietveld refinement. I modeled the glass capillary using
> a SiO2 CIF file and made the crystallite size very small. The issue I am
> having now is that in the weight percent calculation it is saying the glass
> is ~90% of the weight. Does anyone know how I can exclude this phase from
> the weight percent calculation?
>
>
>
> Thanks,
>
> Claire
> ++
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> ++
>
>
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Re: NIST-676a

[Matthew Rowles]

I would use any good single-crystal structure to model the pattern. Refine
cell params as necessary. I would use the NIST certificate as a starting
point, but not an end point.

On Mon, 13 Nov 2023 at 13:07, SMUDUT  wrote:

> Thank you Matthew,
> Really appreciate!
> What about cell parameters and peaks positions? Should I use it from the
> Nist-676a certificate?
> Matej
>
> Poslano iz Outlook za Android 
>
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Re: NIST-676a

[Matthew Rowles]

Hi Matej

You can try IMS135 - high purity alumina.

https://imstandards.com.au/products/

It was certified against some SRM676a we already had in the lab.


Matthew




On Sun, 12 Nov 2023 at 22:42, Matej Dolenec  wrote:

> Dear all,
>
> I am trying to buy NIST-676a but unfortunately unsuccessful ... I was
> trying to find it on NIST, ALDRICH and other sites but the standard is
> out of stock. Does anybody has any information if this standard will be
> available soon and where? If not, which standard should I use instead of
> NIST-676a? I was using this standard for amorphous phase identification.
>
> Regrads, Matej
>
> ++
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> text
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> ++
>
>
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Re: Fitting an unknown amorphous phase

[Matthew Rowles]

Hi Claire

If you just model the phase with generic peaks, and no scale factor, it
will be excluded from the Hill & Howard quantification algorithm. You're
now in relative weight fraction world, and everything is scaled to 100%.
You could also try DDM (Toraya 2016 and others) if you're keen, but
depending on your aversion to patents, you might not want to.

Matthew

On Wed, 1 Nov 2023 at 00:19, Claire Emily Boronski <
claire.boron...@colorado.edu> wrote:

> Hi All,
>
>
>
> I am trying to fit a large unknown amorphous phase. It is not being
> properly fit by my background and being fit by broadening out the peaks of
> other small phases present that should be crystalline. I did XRD-CT on a
> lead pipe scale material and so I cannot spike the sample with a known
> weight percentage of material with a similar absorption coefficient. Is
> there any way that I can fit this unknown phase as just a general unknown
> amorphous material and exclude it from the weight percent calculation?
>
>
>
> Thanks,
>
> Claire
>
>
> ++
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> ++
>
>
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Re: Step-like basline

[Matthew Rowles]

Bad quality mono is always possible. I've got kb coming through with a
current instrument.

On Thu, 7 Sep 2023, 18:56 Reinhard Kleeberg, <
kleeb...@mineral.tu-freiberg.de> wrote:

> Hm, as Philips systems at this time always had combined a
> scintillation counter with a diffracted beam graphite 002 bent
> monochromator, the question arises how the W L series and Cu Kbeta
> lines could reach the detector... Bad quality of the graphite mosaic
> crystal?
>
> Reinhard
>
> Zitat von Le Bail Armel :
>
> > The muscovite data is dated 1996 from an old Philips 1710 diffractometer,
> >
> > vertical sample holder, scintillation counter, not much used because we
> >
> > had better instruments, hence this stupid test ;-)
> >
> > Armel
> >
> >> envoyé : 7 septembre 2023 à 10:57
> >> de : Reinhard Kleeberg 
> >> à : rietveld_l@ill.fr
> >> objet : Re: Step-like basline
> >>
> >> Dear Luca,
> >> sorry, I don't understand the "mosaic crystal" eplanation, especially
> >> not the "non-centre position" issue. IMHO, when the pattern was
> >> measured at a "powder" Bragg-Brentano configuration, in reflection
> >> mode, axial and equatorial divergence maximum ~ 2 degree, the 00l
> >> series of all misoriented crystal blocks can fulfill the diffraction
> >> condition only within the range of the instruments divergence, and the
> >> parafocusing arrangement would reflect such blocks back very close to
> >> the nominal angular position (as it is the case for a powder as well).
> >> So single crystal reflection of big blocks should only be observable
> >> within the total profile of a "normal" ideal powder peak (the
> >> "instrumental" profile"). This is indeed what we see if coarsely
> >> crystalline materials (e.g. quartz sand) are measured on a typical
> >> powder diffractometer: Such peaks are extremely sharp, sometimes split
> >> or doubled, sometimes with "wrong" alpha1/2 intensity ratio, or may
> >> have small additional maxima and may be "edges" in their slopes,
> >> depending on the number or size of crystals, but all these effects are
> >> very close to the correct maximum position (+- <1 degree). So I can't
> >> imagine that the unknown satellites in the mica pattern are
> >> "misoriented-displaced" Cu Kalpha 00l peaks?
> >>
> >> Armel, what type of detector was used for this measurement? If the W L
> >> series was detected, probably no diffracted beam monochromator, and no
> >> Peltier cooled Si drift detector? If so, even more spectral
> >> contamination may come into account. For example, I remember to have
> >> complained about a new Co tube (no company names here) showing
> >> systematic satellites ~ 1 % intensity from standard Si and LaB6 powder
> >> measurements. The wavelength recalculated by Bragg's law was Zn Kalpha
> >> (!!!), confirmed by spectral analysis, the tube Co target was
> >> obviously contaminated. As the satellites in your example in the < 0.x
> >> % magnitude of the Cu K alpha1 intensity, even quite low contamination
> >> of other elements than W may be the source. So it could be
> >> interesting to calculate wavelengths from all positions of the unknown
> >> satellites for the d-spacings of the mica 00l series and see if any
> >> calculated wavelengths do repeat.
> >>
> >> Another thought:
> >> Here we have a single crystal of muscovite. As some of the unexplained
> >> peaks appear to be extremely sharp, what about Renninger (multiple
> >> diffraction) hkl peaks? Maybe there are enough lattice planes in the
> >> monoclinic mica structure to give a chance for multiple diffraction to
> >> get registered by a divergent beam (Bragg-Brentano) configuration?
> >> Such peak positions appear to be unsystematic, with no relatiion to
> >> the Cu Kalpha 00l.
> >>
> >> However, a take-home message of your example should be: Do never
> >> measure single crystals in parafocusing geometry without safely
> >> monochromatic radiation ;-)
> >>
> >> Best regards
> >>
> >> Reinhard
> >>
> >> Zitat von Luca Lutterotti :
> >>
> >>> It is call graininess, as Miguel said before, these are mosaic
> >>> single crystals and depending on your source (divergence, spot
> >>> dimension at different angles etc.) you get each mosaic crystal to
> >>> create a diffraction peak that especially at low two-theta angle may
> >>> be displaced a lot from its theoretical position because it is
> >>> diffracting from a non center position. This is what you get also
> >>> when you analyse samples with extremely large grains. If you use a
> >>> 2D detector instead of scanning with a point or small psd, you will
> >>> see all these individual grain or mosaic crystals diffracting around
> >>> their ideal spot or if it is a sample with just large grains,
> >>> distributed around the Laue circle. More the grain is on a lateral
> >>> position respect to the center of the beam, more it is displaced in
> >>> two-theta. At higher angle your beam size on the sample is smaller
> >>> and there is less displacement for geometrical reasons.
> >>> I like 

Re: [EXTERNAL] Re: [EXT] [External] Re: Step-like basline

[Matthew Rowles]

rved. Now I would add that I may not define your Bruker clean
>> >>>> and optimised, because for this kind of samples, wafers and
>> >>>> extremely textured thin films, it would be better to have a
>> >>>> monochromator in the incident beam and not a Ni filtered (I would
>> >>>> more say it is a requirement). It was already showed many times in
>> >>>> the past as a monochromator in the incident beam is a necessity
>> >>>> for this materials to avoid all the "physical artifacts" created
>> >>>> by the strong intensity and not clean Kalpha radiation.
>> >>>>
>> >>>> Best regards,
>> >>>>
>> >>>> Luca
>> >>>>
>> >>>> <http://www.unitn.it/>
>> >>>>
>> >>>> Luca Lutterotti
>> >>>> Dipartimento di Ingegneria Industriale
>> >>>> Università di Trento
>> >>>> via Sommarive, 9 - 38123 Trento (Italy)
>> >>>> tel. +39 0461 2824-14 (Office), -34 (X-Ray lab)
>> >>>>
>> >>>>
>> >>>> 
>> >>>>
>> >>>> Maud: http://maud.radiographema.com <http://maud.radiographema/>
>> >>>>
>> >>>>
>> >>>>> On 4 Sep 2023, at 12:20, Habib Boughzala
>> >>>>>  wrote:
>> >>>>>
>> >>>>> Many thanks Reinhard,
>> >>>>>
>> >>>>> That's exactly what I wanted to say by  "I can assure that our
>> >>>>> Bruker D8 is clean and optimized!"
>> >>>>> Otherwise, in some other cases of well conditioned thin film no
>> >>>>> similar phenomenon is observed!
>> >>>>> So, yes, it's obviously possible that your point of view is right.
>> >>>>>
>> >>>>> Regards
>> >>>>> Habib
>> >>>>>
>> >>>>>
>> >>>>> -- Message d'origine --
>> >>>>> De "Reinhard Kleeberg" > >>>>> <mailto:kleeb...@mineral.tu-freiberg.de>>
>> >>>>> À "Habib Boughzala" > boughz...@yahoo.com>>
>> >>>>> Cc rietveld_l@ill.fr <mailto:rietveld_l@ill.fr>
>> >>>>> Date 04/09/2023 11:07:50
>> >>>>> Objet Re: Re[2]: [EXT] Re: [External] Re: Step-like basline
>> >>>>>
>> >>>>>> Dear Habib,
>> >>>>>> the phenomenom "satellites or edges" originates from the
>> >>>>>> diffraction process. The critical parameters are:
>> >>>>>> - spectral pureness of the primary beam (primary beam
>> >>>>>> monochromator, tube spectral contamination like W...)
>> >>>>>> - the use of K beta absorbtion filter (and its thickness)
>> >>>>>> - the energy resolution ("window") of the detector system.
>> >>>>>> Even a D8 system may be equipped with different types of
>> >>>>>> detectors, slits and energy limits can be set differently for an
>> >>>>>> identical configuration, and quite often satellite peaks may
>> >>>>>> appear later in the time of use (aging of the tube produces more
>> >>>>>> W L, Fe filters may corrode and get perforated...). So it is
>> >>>>>> strictly recommended to check the instrument peridically, by
>> >>>>>> measuring a full pattern of a profile standard (LaB6 or Si or
>> >>>>>> similar).
>> >>>>>> Greetings
>> >>>>>> Reinhard
>> >>>>>>
>> >>>>>> Zitat von Habib Boughzala > >>>>>> <mailto:boughz...@yahoo.com>>:
>> >>>>>>
>> >>>>>>> Dear all,
>> >>>>>>> I would like to send you my witness related to this kind of
>> >>>>>>> observation.
>> >>>>>>> I can assure that our Bruker D8 is clean and optimized!
>> >>>>>>>
>> >>>>>>> In many cases of well conditioned thin film (spin coating or
>> >>>>>>> controlled diffusion) material this kind of phenomenon is
>> >>>

Re: [EXT] Re: [External] Re: Step-like basline

[Matthew Rowles]

Topas can model them quite well. The functionality was introduced in
version 5.

On Mon, 4 Sep 2023, 00:54 Kurt Leinenweber,  wrote:

> Hi,  Are these things modeled in Rietveld programs, by chance?  It seems
> like a lot of baggage to put in a refinement but if it makes the results
> better…
>
>
>
>- Kurt
>
>
>
> *From:* rietveld_l-requ...@ill.fr  *On Behalf
> Of *Thomas Gegan
> *Sent:* Sunday, September 3, 2023 9:16 AM
> *To:* Bish, David L ; Shay Tirosh ;
> Fernando Igoa 
> *Cc:* Rietveld List (rietveld_l@ill.fr) 
> *Subject:* RE: [EXT] Re: [External] Re: Step-like basline
>
>
>
> I agree with a Ni absorption edge, possibly with a Kβ peak around 38° 2θ.
>
>
>
> *Tom Gegan*
> Chemist III
>
>
>
> Phone: +1 732 205-5111, Email: tom.ge...@basf.com
> Postal Address: BASF Corporation, , 25 Middlesex Essex Turnpike, 08830
> Iselin, United States
>
>
>
> *From:* rietveld_l-requ...@ill.fr  *On Behalf
> Of *Bish, David L
> *Sent:* Sunday, September 3, 2023 7:08 AM
> *To:* Shay Tirosh ; Fernando Igoa <
> fer.igoa.1...@gmail.com>
> *Cc:* Rietveld List (rietveld_l@ill.fr) 
> *Subject:* [EXT] Re: [External] Re: Step-like basline
>
>
>
> Some people who received this message don't often get email from
> b...@indiana.edu. Learn why this is important
> 
>
> Hello Shay,
>
> I think it is probably related to "tube tails". You can read about this in
> the literature (e.g., on the BGMN web site) and you can model it in some
> Rietveld software such as Topas. You don't normally notice this but it
> becomes apparent with higher-intensity peaks.
>
>
>
> Regards,
>
> Dave
> --
>
> *From:* rietveld_l-requ...@ill.fr  on behalf
> of Fernando Igoa 
> *Sent:* Sunday, September 3, 2023 3:06 AM
> *To:* Shay Tirosh 
> *Cc:* Rietveld List (rietveld_l@ill.fr) 
> *Subject:* [External] Re: Step-like basline
>
>
>
> This message was sent from a non-IU address. Please exercise caution when
> clicking links or opening attachments from external sources.
>
>
>
> Hey Shay,
>
>
>
> Are you using a motorized slit during the measurement? These may open up
> abruptly to compensate for the angular dependence of the footprint and thus
> generate an abrupt increase in the intensity.
>
>
>
> Hope it helps :)
>
>
>
> On Sun, Sep 3, 2023, 8:50 AM Shay Tirosh  wrote:
>
> Dear Rietvelders
>
> I am attaching a zoom-in on a diffraction profile.
>
> My question is what is the origin of the step-like profile next to a very
> large reflection peak?
>
> Is it a sample preparation problem?
>
> Is it part of the baseline?
>
> Thanks
>
> Shay
>
> --
>
>
>
>
>
>
>
>
>
>
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> 
> ++
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
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++

Re: Step-like basline

[Matthew Rowles]

That's a k beta peak followed by a metal foil absorption edge followed by
the K alpga peak.

On Sun, 3 Sep 2023, 14:50 Shay Tirosh,  wrote:

> Dear Rietvelders
> I am attaching a zoom-in on a diffraction profile.
> My question is what is the origin of the step-like profile next to a very
> large reflection peak?
> Is it a sample preparation problem?
> Is it part of the baseline?
> [image: image.png]
> Thanks
> Shay
> --
>
>
>
>
>
>
>
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
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++

Re: ITC scattering factors: Table 6.1.1.1: Ne

[Matthew Rowles]

Ta for that Stephen

The sum-of-gaussian parameterisation has to have some data to fit against
to get their values, and the IT is kind of the publication of record.

I've just requested that edition (I think it's that one) from the library;
I've also got some issues with some other elements and their
parameterisations...


Matthew



On Tue, 11 Apr 2023 at 20:55, Peter Stephens 
wrote:

> The 1992 edition lists 2.790 for s = 0.60 and 2.517 for 0.65, so I guess
> that tells you when the error appeared.
>
> On a side note, and at some risk of being flamed, I'm curious why any
> crystallographer would care.
>
> Best to all,
> Peter
>
> **
> Peter W. Stephens
> SUNY Distinguished Professor Emeritus
> Department of Physics and Astronomy
> Stony Brook University
>
>
>
>
> On Tue, Apr 11, 2023 at 7:12 AM Matthew Rowles  wrote:
>
>> Hi all
>>
>> Does anyone have current/past editions of IT volume C lying around?
>> I think there is a typo in the scattering factors for neutral Ne in Table
>> 6.1.1.1. I have the 3rd edition (2004)
>>
>> For s=0.60 and 0.65, the scattering factor is given as 2.517. From Cromer
>> & Mann (1968)*, I'd expect the first value to be about 2.787, but the other
>> values don't match exactly, either.
>>
>> Any ideas on what the actual value should be?
>>
>>
>> Thanks
>>
>> Matthew
>>
>> *https://www.osti.gov/servlets/purl/4555098
>> ++
>> Please do NOT attach files to the whole list > >
>> Send commands to  eg: HELP as the subject with no body
>> text
>> The Rietveld_L list archive is on
>> http://www.mail-archive.com/rietveld_l@ill.fr/
>> ++
>>
>>
++
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++

ITC scattering factors: Table 6.1.1.1: Ne

[Matthew Rowles]

Hi all

Does anyone have current/past editions of IT volume C lying around? I think
there is a typo in the scattering factors for neutral Ne in Table 6.1.1.1.
I have the 3rd edition (2004)

For s=0.60 and 0.65, the scattering factor is given as 2.517. From Cromer &
Mann (1968)*, I'd expect the first value to be about 2.787, but the other
values don't match exactly, either.

Any ideas on what the actual value should be?


Thanks

Matthew

*https://www.osti.gov/servlets/purl/4555098
++
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++

Re: scattering factor for O2- ?

[Matthew Rowles]

Warning, anecdote ahead! (and this wasn't the point of my original post...)

I get better (flatter difference plot) fits with SRM676A using charged
atoms (Al+3, O-2) than I do with neutral. (Co Ka, lab BB diffractometer)

https://imgur.com/a/83s1Bpz (sqrt scale)

I intend on looking in more depth (the pics above are the current extent of
my investigation), as I'm trying to calibrate some new QPA QC standards,
and found some issues, so I ended up wandering into a can of worms...

Matthew

On Wed, 22 Feb 2023 at 02:11, Toby, Brian H.  wrote:

> I am going to make the comment that (A) neutral atom form factors are
> probably closer to the actual electron distribution in most materials where
> there is significant covalent bonding (~= almost everything) and (B) even
> if that were not true, the difference between O, O1- and O2- is probably
> pretty minor for powder diffraction, so the choice does not matter. Except
> at very low angle, the form factor curves are just about the same for
> ionized atoms as neutral ones. (This is understandable since ionization
> only affects the outer shell electrons.) So, other than a small change in
> the first reflection or two, easily swamped by experimental artifacts, one
> just does not see any difference.
>
> I personally use only neutral atom form factors.
>
> Brian
>
>
> On Feb 21, 2023, at 4:10 AM, Matthew Rowles  wrote:
>
> Thanks all
>
> It looks like fat fingers all around!
>
> W doesn't contain O2-, does contain O-
> RR _does_ contain O2-, doesn't contain O- (every version of the
> waasameir data I've found online has this typo, so I'm pretty sure they're
> all the same file.)
>
> Now just to cross-check the data to see if they're the same (and
> actually _read_ the papers)
>
> I'll also check out the other papers, and start looking for some N3-.
>
> Thanks
>
>
> Matthew
>
>
>
>
>
>
>
>
> On Tue, 21 Feb 2023 at 17:44, Kern, Arnt  wrote:
>
>> Hello Daniel, hello all!
>>
>>
>>
>> Daniel, you are right. I just obtained the Hovestreydt paper, he actually
>> published a 9 coefficients representation.
>>
>>
>>
>> My apologies!
>>
>>
>>
>> Cheers,
>>
>>
>>
>> Arnt
>>
>>
>>
>>
>> -Bruker Confidential-
>>
>> *Von:* rietveld_l-requ...@ill.fr  *Im Auftrag
>> von *Többens, Daniel
>> *Gesendet:* Dienstag, 21. Februar 2023 09:58
>> *An:* rietveld_l@ill.fr
>> *Betreff:* Re: scattering factor for O2- ?
>>
>>
>>
>> Hello Arnt,
>>
>> I believe you are probably mistaken. The file at GitHub cites at the
>> source of most of its scattering factors either the paper of Waasmaier &
>> Kirfel ("New Analytical Scattering Factor Functions for Free Atoms and
>> Ions", D. Waasmaier & A. Kirfel, Acta Cryst. A 95) or the International
>> Tables, with the sole exception of "Fit for O1- based on the tabulated
>> values of Table 2 (D. Rez, P. Rez & I.Grant, Acta Cryst. (1994), A50,
>> 481-497)."
>>
>> This is most certainly a typing error, as neither of the former two
>> contains values for O2-, while the paper of Rez does not contains values
>> for O2-, but not for O1-. I would be very surprised if the values there
>> were not fitted to the table of Rez.
>>
>> Just for the sake of completeness, there are at least two more papers
>> with scattering factors for O2-:
>>
>> Schmidt, P.C., K.D. Sen, and A. Weiss, The Spherical Crystal-Potential
>> and Physical-Properties of Ions in Crystals - a Hf-Calculation for the
>> 10,18, and 36-Electron Closed Shell Ions of X-Ray-Scattering Factors,
>> Diamagnetic Susceptibilities, and Dipole Polarizabilities. Berichte Der
>> Bunsen-Gesellschaft - Physical Chemistry Chemical Physics, 1980. 84(12): p.
>> 1240-1251.
>>
>> Azavant, P. and A. Lichanot, X-Ray-Scattering Factors of Oxygen and
>> Sulfur Ions - an Ab initio Hartree-Fock Calculation. Acta Crystallographica
>> Section A, 1993. 49: p. 91-97.
>>
>> Good Luck to everyone out there,
>> Daniel Többens
>>
>> Am 21.02.2023 um 07:52 schrieb Kern, Arnt:
>>
>> Hi Matthew,
>>
>>
>>
>> I am pretty sure, this is
>>
>>
>>
>> “On the atomic scattering factor for O2-“
>>
>> E. Hovestreydt
>>
>>
>>
>> Acta Cryst. (1983). A39, 268-269
>>
>> https://doi.org/10.1107/S0108767383000550
>>
>>
>>
>> I don’t have the paper at hand, unfortunately.
>>
>>
>>
>> Cheers,
>>
>>
>>
>> Arnt
>>

Re: scattering factor for O2- ?

[Matthew Rowles]

Thanks all

It looks like fat fingers all around!

W doesn't contain O2-, does contain O-
RR _does_ contain O2-, doesn't contain O- (every version of the waasameir
data I've found online has this typo, so I'm pretty sure they're all the
same file.)

Now just to cross-check the data to see if they're the same (and
actually _read_ the papers)

I'll also check out the other papers, and start looking for some N3-.

Thanks


Matthew








On Tue, 21 Feb 2023 at 17:44, Kern, Arnt  wrote:

> Hello Daniel, hello all!
>
>
>
> Daniel, you are right. I just obtained the Hovestreydt paper, he actually
> published a 9 coefficients representation.
>
>
>
> My apologies!
>
>
>
> Cheers,
>
>
>
> Arnt
>
>
>
>
>
> -Bruker Confidential-
>
> *Von:* rietveld_l-requ...@ill.fr  *Im Auftrag
> von *Többens, Daniel
> *Gesendet:* Dienstag, 21. Februar 2023 09:58
> *An:* rietveld_l@ill.fr
> *Betreff:* Re: scattering factor for O2- ?
>
>
>
> Hello Arnt,
>
> I believe you are probably mistaken. The file at GitHub cites at the
> source of most of its scattering factors either the paper of Waasmaier &
> Kirfel ("New Analytical Scattering Factor Functions for Free Atoms and
> Ions", D. Waasmaier & A. Kirfel, Acta Cryst. A 95) or the International
> Tables, with the sole exception of "Fit for O1- based on the tabulated
> values of Table 2 (D. Rez, P. Rez & I.Grant, Acta Cryst. (1994), A50,
> 481-497)."
>
> This is most certainly a typing error, as neither of the former two
> contains values for O2-, while the paper of Rez does not contains values
> for O2-, but not for O1-. I would be very surprised if the values there
> were not fitted to the table of Rez.
>
> Just for the sake of completeness, there are at least two more papers with
> scattering factors for O2-:
>
> Schmidt, P.C., K.D. Sen, and A. Weiss, The Spherical Crystal-Potential and
> Physical-Properties of Ions in Crystals - a Hf-Calculation for the 10,18,
> and 36-Electron Closed Shell Ions of X-Ray-Scattering Factors, Diamagnetic
> Susceptibilities, and Dipole Polarizabilities. Berichte Der
> Bunsen-Gesellschaft - Physical Chemistry Chemical Physics, 1980. 84(12): p.
> 1240-1251.
>
> Azavant, P. and A. Lichanot, X-Ray-Scattering Factors of Oxygen and Sulfur
> Ions - an Ab initio Hartree-Fock Calculation. Acta Crystallographica
> Section A, 1993. 49: p. 91-97.
>
> Good Luck to everyone out there,
> Daniel Többens
>
> Am 21.02.2023 um 07:52 schrieb Kern, Arnt:
>
> Hi Matthew,
>
>
>
> I am pretty sure, this is
>
>
>
> “On the atomic scattering factor for O2-“
>
> E. Hovestreydt
>
>
>
> Acta Cryst. (1983). A39, 268-269
>
> https://doi.org/10.1107/S0108767383000550
>
>
>
> I don’t have the paper at hand, unfortunately.
>
>
>
> Cheers,
>
>
>
> Arnt
>
>
>
>
>
>
>
> -Bruker Confidential-
>
> *Von:* rietveld_l-requ...@ill.fr 
>  *Im Auftrag von *Matthew Rowles
> *Gesendet:* Dienstag, 21. Februar 2023 01:38
> *An:* RIETVELD_L Distribution List  
> *Betreff:* scattering factor for O2- ?
>
>
>
> **EXTERNAL EMAIL**
>
> Hi all
>
>
>
> I've been looking at atomic scattering factors recently, and in
> particular, the 11-coefficient parameterisation by Waasmaier and Kirfel [1].
>
>
>
> In their paper, they give a parameterisation for O and O-, but in tables I
> can find online (eg libdiffpy/f0_WaasKirf.dat at master ·
> diffpy/libdiffpy (github.com)
> <https://github.com/diffpy/libdiffpy/blob/master/src/runtime/f0_WaasKirf.dat>),
> there is also an entry for O2-.
>
>
>
> Does anybody know where this came from?
>
>
>
> Thanks
>
>
>
> Matthew
>
>
>
>
>
> [1] D. Waasmaier & A. Kirfel, New Analytical Scattering Factor Functions
> for Free Atoms and Ions for Free Atoms and Ions,  Acta Cryst. (1995). A51,
> 416-413
>
>
>
>
>
> ++
>
> Please do NOT attach files to the whole list  
> 
>
> Send commands to   eg: HELP as the subject 
> with no body text
>
> The Rietveld_L list archive is on 
> http://www.mail-archive.com/rietveld_l@ill.fr/
>
> ++
>
>
>
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
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++

scattering factor for O2- ?

[Matthew Rowles]

Hi all

I've been looking at atomic scattering factors recently, and in particular,
the 11-coefficient parameterisation by Waasmaier and Kirfel [1].

In their paper, they give a parameterisation for O and O-, but in tables I
can find online (eg libdiffpy/f0_WaasKirf.dat at master · diffpy/libdiffpy
(github.com)
),
there is also an entry for O2-.

Does anybody know where this came from?

Thanks

Matthew


[1] D. Waasmaier & A. Kirfel, New Analytical Scattering Factor Functions
for Free Atoms and Ions for Free Atoms and Ions,  Acta Cryst. (1995). A51,
416-413
++
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++

2023 IUCr Microsymposium “Industrial and Engineering Powder Diffraction”

[Matthew Rowles]

Dear fellow powder diffractionists,


We would like to encourage you to consider submitting an abstract to the
2023 IUCr Microsymposium “Industrial and Engineering Powder Diffraction”,
which is sponsored by the Commissions on Powder Diffraction and Neutron
Scattering, and chaired by Matthew Rowles and Anna Paradowska. The abstract
submission deadline is looming (21 Feb 2023) and we still have lots of room
for submissions. Jim Kaduk is an invited speaker and will highlight the
session. We hope you will share what you have learned about powder
diffraction using X-ray or neutron sources (or even electrons!).


*Symposium description: X-ray and neutron powder diffraction play an
important role in quality control for industries such as metals
manufacturing, mining, and cement production, where issues such as phase
identification and quantification are of great importance. They are also of
great importance in studies of stress, texture, and failure in engineering
components. Here the penetrating power of neutrons and high energy X-rays
enables non-destructive approaches, including spatially resolved methods..*



The congress will be held in Melbourne, Australia, August 22- August 29
2023 (https://iucr2023.org/
<https://nam04.safelinks.protection.outlook.com/?url=https%3A%2F%2Fiucr2023.org%2F=05%7C01%7CCora.Lind%40utoledo.edu%7C64745fd817d34294eb4908dad3bca449%7C1d6b1707baa94a3da8f8deabfb3d467b%7C0%7C0%7C638055104481013921%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C=HdgwnaX0tOvcfS7Go6rI7BrSjJ2vvSlhia%2FBwzHYemE%3D=0>).
The triennial Congress of the IUCr is the preeminent international
scientific meetings for crystallographers worldwide and attracts a large
and diverse audience. It is our ambition that there will be a strong
in-person attendance at the congress and that the speakers in the
microsymposium will present their lectures in Melbourne.



Regards



Matthew Rowles

Co-chair, 2023 IUCr Microsymposium “Industrial and Engineering Powder
Diffraction”
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++

Re: "2d materials don't exist" editorial??

[Matthew Rowles]

If you want to have a rant, just have a look at the wikipedia page for
single-layer materials.

Phosphorene is particularly egregious:
https://en.wikipedia.org/wiki/File:Phosphorene_structure.png

On Fri, 30 Dec 2022 at 20:30, Radovan Cerny  wrote:

> OK, I understand. Thank you Mike.
>
> The graphene is then 2P material with the layer group p6/mmm. Can somebody
> give me an example of a 2D material with the plane group p6mm?
>
> Thank you
>
> Radovan
>
> Radovan Cerny
> Laboratoire de Cristallographie
> Université de Genève
> 24, quai Ernest-Ansermet
> CH-1211 Geneva 4, Switzerland
> Phone  : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08
> mailto : radovan.ce...@unige.ch
> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
> --
> *De :* Mike Glazer 
> *Envoyé :* vendredi 30 décembre 2022 12:20
> *À :* Radovan Cerny ; Matthew Rowles <
> rowle...@gmail.com>
> *Cc :* RIETVELD_L Distribution List 
> *Objet :* Re: "2d materials don't exist" editorial??
>
> Radovan
> Not quite. Graphene  is a 3d material but has periodicity in 2d making its
> symmetry given by one of the 80 subperiodic layer groups.
> Mike Glazer
>
> Get Outlook for Android <https://aka.ms/AAb9ysg>
> --
> *From:* rietveld_l-requ...@ill.fr  on behalf
> of Radovan Cerny 
> *Sent:* Friday, December 30, 2022 11:07:52 AM
> *To:* Matthew Rowles 
> *Cc:* RIETVELD_L Distribution List 
> *Subject:* RE: "2d materials don't exist" editorial??
>
> Thank you Matt,
>
> for bringing this subject which I have never taken too seriously, butt as
> Massimo pointed out in his paper, there are important differences in what
> symmetry allows for 2D and what for 2P, for example.
>
> I feel now a bit responsible, because my colleagues at the Quantum matter
> dpt. at UNIGE are working on layered pnictides and call them always 2D
> materials, which is not correct. They are 2P materials. I will try to
> educate them now, even if I am retired. Maybe they can call them 2D
> materials if they talk about the physical properties rather than about the
> structure?
> I have already tried to introduce then in the OD theory for polytypic
> structures, but without too much success. They prefer to do their DFT
> modelling rather than have a look on what has been already done.
>
> A test, whether I have properly understood Massimo: Graphen is 2D
> material, but when I attach anything to it or take more than one layer of
> graphen, it becomes 2P material, right?
>
> Have a nice end of the year
>
> Radovan
>
> Radovan Cerny
> Laboratoire de Cristallographie
> Université de Genève
> 24, quai Ernest-Ansermet
> CH-1211 Geneva 4, Switzerland
> Phone  : [+[41] 22] 37 964 50, FAX : [+[41] 22] 37 961 08
> mailto : radovan.ce...@unige.ch
> URL: http://www.unige.ch/sciences/crystal/cerny/rcerny.htm
> --
> *De :* rietveld_l-requ...@ill.fr  de la part
> de Matthew Rowles 
> *Envoyé :* lundi 26 décembre 2022 11:08
> *À :* Alan W Hewat 
> *Cc :* Leopoldo Suescun ; RIETVELD_L Distribution
> List 
> *Objet :* Re: "2d materials don't exist" editorial??
>
> These are good learning events.
>
> .
>
> And it doesn't make much third dimensional periodicity to make a layered
> material act as a bulk 3d material (see recent publications by Kate
> Putman), or at least from a powder diffraction point of view.
>
>
>
>
> On Sun, 25 Dec 2022, 12:40 Alan W Hewat, 
> wrote:
>
> Symmetry is the Crystallographer's first love, but periodicity is more
> important in deciding to call a structure 2D or 3D. Powder diffraction in
> particular showed that symmetry is ephemeral in many materials, whose
> symmetry is lowered when they are cooled. This symmetry is just the
> consequence of averaging over time and space. Yet we remain fascinated by
> symmetry, sometimes imposing it on Nature when it has no physical
> consequences.
>
> Great to have a little philosophy to go with the Christmas pudding. Thanks
> Mathew.
> 
> Dr Alan Hewat, NeutronOptics
> Grenoble, FRANCE (from phone)
> alan.he...@neutronoptics.com
> +33.476984168 VAT:FR79499450856
> http://NeutronOptics.com/hewat
> ___
>
>
> On Sun, 25 Dec 2022, 01:16 Matthew Rowles,  wrote:
>
> I didn't even know of the existence of the frieze, rod, and layer groups
> until I read this comment.
>
> So, I guess it's working?
>
> On Sat, 24 Dec 2022, 22:49 Leopoldo Suescun,  wrote:
>
> Hi all,
>
> Thank you Matt for bringing up this issue.
>
> Massimo Nespolo has been fighting for the correct descriptio

QPA calculation from Rietveld refinements

[Matthew Rowles]

Hi all

Are there any Rietveld programs that use the Bish and Howard approach
directly (instead of Hill & Howard) to calculate QPA?

ie w_i = s_i * rho_i / Sum(s_j * rho _j)

instead of

w_i = S_i * Z_i * M_i * V_i / Sum( S_j * Z_j * M_j * V_j)


where
w_i - weight fraction of phase i
s_i - Bish & Howard scale factor of phase i
S_i - Hill & Howard scale factor of phase i
rho_i - density of phase i
Z_i - number of formula units per unit cell of phase i
M_i - mass of formula unit of phase i
V_i - unit cell volume of phase i


They are equivalent, as long as the intensities in the B case are
pre-scaled by 1/V^2.



Regards

Matthew
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++

Re: "2d materials don't exist" editorial??

[Matthew Rowles]

These are good learning events.

.

And it doesn't make much third dimensional periodicity to make a layered
material act as a bulk 3d material (see recent publications by Kate
Putman), or at least from a powder diffraction point of view.




On Sun, 25 Dec 2022, 12:40 Alan W Hewat, 
wrote:

> Symmetry is the Crystallographer's first love, but periodicity is more
> important in deciding to call a structure 2D or 3D. Powder diffraction in
> particular showed that symmetry is ephemeral in many materials, whose
> symmetry is lowered when they are cooled. This symmetry is just the
> consequence of averaging over time and space. Yet we remain fascinated by
> symmetry, sometimes imposing it on Nature when it has no physical
> consequences.
>
> Great to have a little philosophy to go with the Christmas pudding. Thanks
> Mathew.
> 
> Dr Alan Hewat, NeutronOptics
> Grenoble, FRANCE (from phone)
> alan.he...@neutronoptics.com
> +33.476984168 VAT:FR79499450856
> http://NeutronOptics.com/hewat
> ___________
>
>
> On Sun, 25 Dec 2022, 01:16 Matthew Rowles,  wrote:
>
>> I didn't even know of the existence of the frieze, rod, and layer groups
>> until I read this comment.
>>
>> So, I guess it's working?
>>
>> On Sat, 24 Dec 2022, 22:49 Leopoldo Suescun,  wrote:
>>
>>> Hi all,
>>>
>>> Thank you Matt for bringing up this issue.
>>>
>>> Massimo Nespolo has been fighting for the correct description of
>>> structures, specially focusing on symmetry and proper terminology, for
>>> years (see his many articles on the misuse of lattice, sublattice,
>>> superlattice, etc).
>>>
>>> He has, as well, been educating crystallographers of all ages in
>>> symmetry concepts and use through IUCr's MaThCryst Commision and
>>> Internationa School on Fundamental Crystallograpy courses around the world.
>>>
>>> He'll probably be remembered by many as a Dick Marsh of symmetry.
>>>
>>> I guess it is the task of all us, crystallographers, to promote the
>>> correct use of terminology related to crystal structures, as suggested by
>>> IUCr conventions included in IUCr Dictionary and modern literature.
>>>  https://dictionary.iucr.org/Main_Page
>>>
>>> Best wishes for all of you that, in a way or another have this as a
>>> special week in your calendars, and Happy New Year for all.
>>>
>>> Leo
>>>
>>> El sáb, 24 de dic. de 2022 05:01, Matthew Rowles 
>>> escribió:
>>>
>>>> Hi all
>>>>
>>>> I think this is the one
>>>>
>>>> https://scripts.iucr.org/cgi-bin/paper?S1600576721001606
>>>>
>>>> Matthew
>>>>
>>>> On Fri, 23 Dec 2022, 10:00 Matthew Rowles,  wrote:
>>>>
>>>>> This might be it, but the link is to the iucr homepage:
>>>>>
>>>>> Google: "letter to the editor" two-dimensional "layer groups" graphene
>>>>> iucr
>>>>>
>>>>> [image: image.png]
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Fri, 23 Dec 2022 at 09:53, Matthew Rowles 
>>>>> wrote:
>>>>>
>>>>>> Hi all
>>>>>>
>>>>>> A while ago (months, years??) I recall reading an editorial or letter
>>>>>> to the editor about materials being referred to as "2D", and how they're
>>>>>> actually 3D, and just periodic in the plane, and should be referred to as
>>>>>> 2P and a relevant layer group.
>>>>>>
>>>>>> Does anyone recall such a thing?
>>>>>>
>>>>>>
>>>>>> Thanks
>>>>>>
>>>>>> Matthew
>>>>>>
>>>>> ++
>>>> Please do NOT attach files to the whole list
>>>> 
>>>> Send commands to  eg: HELP as the subject with no
>>>> body text
>>>> The Rietveld_L list archive is on
>>>> http://www.mail-archive.com/rietveld_l@ill.fr/
>>>> ++
>>>>
>>>> ++
>> Please do NOT attach files to the whole list > >
>> Send commands to  eg: HELP as the subject with no body
>> text
>> The Rietveld_L list archive is on
>> http://www.mail-archive.com/rietveld_l@ill.fr/
>> ++
>>
>>
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++

Re: "2d materials don't exist" editorial??

[Matthew Rowles]

I didn't even know of the existence of the frieze, rod, and layer groups
until I read this comment.

So, I guess it's working?

On Sat, 24 Dec 2022, 22:49 Leopoldo Suescun,  wrote:

> Hi all,
>
> Thank you Matt for bringing up this issue.
>
> Massimo Nespolo has been fighting for the correct description of
> structures, specially focusing on symmetry and proper terminology, for
> years (see his many articles on the misuse of lattice, sublattice,
> superlattice, etc).
>
> He has, as well, been educating crystallographers of all ages in symmetry
> concepts and use through IUCr's MaThCryst Commision and Internationa School
> on Fundamental Crystallograpy courses around the world.
>
> He'll probably be remembered by many as a Dick Marsh of symmetry.
>
> I guess it is the task of all us, crystallographers, to promote the
> correct use of terminology related to crystal structures, as suggested by
> IUCr conventions included in IUCr Dictionary and modern literature.
>  https://dictionary.iucr.org/Main_Page
>
> Best wishes for all of you that, in a way or another have this as a
> special week in your calendars, and Happy New Year for all.
>
> Leo
>
> El sáb, 24 de dic. de 2022 05:01, Matthew Rowles 
> escribió:
>
>> Hi all
>>
>> I think this is the one
>>
>> https://scripts.iucr.org/cgi-bin/paper?S1600576721001606
>>
>> Matthew
>>
>> On Fri, 23 Dec 2022, 10:00 Matthew Rowles,  wrote:
>>
>>> This might be it, but the link is to the iucr homepage:
>>>
>>> Google: "letter to the editor" two-dimensional "layer groups" graphene
>>> iucr
>>>
>>> [image: image.png]
>>>
>>>
>>>
>>>
>>> On Fri, 23 Dec 2022 at 09:53, Matthew Rowles  wrote:
>>>
>>>> Hi all
>>>>
>>>> A while ago (months, years??) I recall reading an editorial or letter
>>>> to the editor about materials being referred to as "2D", and how they're
>>>> actually 3D, and just periodic in the plane, and should be referred to as
>>>> 2P and a relevant layer group.
>>>>
>>>> Does anyone recall such a thing?
>>>>
>>>>
>>>> Thanks
>>>>
>>>> Matthew
>>>>
>>> ++
>> Please do NOT attach files to the whole list > >
>> Send commands to  eg: HELP as the subject with no body
>> text
>> The Rietveld_L list archive is on
>> http://www.mail-archive.com/rietveld_l@ill.fr/
>> ++
>>
>>
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++

Re: "2d materials don't exist" editorial??

[Matthew Rowles]

Hi all

I think this is the one

https://scripts.iucr.org/cgi-bin/paper?S1600576721001606

Matthew

On Fri, 23 Dec 2022, 10:00 Matthew Rowles,  wrote:

> This might be it, but the link is to the iucr homepage:
>
> Google: "letter to the editor" two-dimensional "layer groups" graphene iucr
>
> [image: image.png]
>
>
>
>
> On Fri, 23 Dec 2022 at 09:53, Matthew Rowles  wrote:
>
>> Hi all
>>
>> A while ago (months, years??) I recall reading an editorial or letter to
>> the editor about materials being referred to as "2D", and how they're
>> actually 3D, and just periodic in the plane, and should be referred to as
>> 2P and a relevant layer group.
>>
>> Does anyone recall such a thing?
>>
>>
>> Thanks
>>
>> Matthew
>>
>
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++

Re: "2d materials don't exist" editorial??

[Matthew Rowles]

This might be it, but the link is to the iucr homepage:

Google: "letter to the editor" two-dimensional "layer groups" graphene iucr

[image: image.png]




On Fri, 23 Dec 2022 at 09:53, Matthew Rowles  wrote:

> Hi all
>
> A while ago (months, years??) I recall reading an editorial or letter to
> the editor about materials being referred to as "2D", and how they're
> actually 3D, and just periodic in the plane, and should be referred to as
> 2P and a relevant layer group.
>
> Does anyone recall such a thing?
>
>
> Thanks
>
> Matthew
>
++
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++

"2d materials don't exist" editorial??

[Matthew Rowles]

Hi all

A while ago (months, years??) I recall reading an editorial or letter to
the editor about materials being referred to as "2D", and how they're
actually 3D, and just periodic in the plane, and should be referred to as
2P and a relevant layer group.

Does anyone recall such a thing?


Thanks

Matthew
++
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++

Re: Generating space group general positions - issues implementing Shmueli (1984)

[Matthew Rowles]

2  (1/2, 1/2,   0)  x,x-1/4,0
> !   -1   0,0,0
> !t  (0  , 1/2, 1/2)
> !t  (1/2,   0, 1/2)
> Note for example the difference in the 5th generator -1 = 1bar.
>
> Another note, the generators in the ITA are listed such that starting from
> coordinates x,y,z you apply
> the 1st generator to these coordinates. Then you can apply the second
> generator to all previously
> generated position and so on. You do not need a recursive algorithm to
> generate all positions. for
> special positions, you can terminate once a previous coordinate is
> reproduced.
>
> Feel free to check out the generators and the generation of symmetry
> matrices in my DISCUS code
> (generate_mod.f90 and spcgr_apply.f90 at
> https://github.com/tproffen/DiffuseCode
>
>
>
> Hope this helps
> Reinhard Neder
>
>
> Am 08.11.22 um 04:42 schrieb Matthew Rowles:
>
> Hi all
>
> For various reasons, I'm writing some code to generate the general
> positions of the space groups. I'm trying to follow the implementation of
> Shmueli in their 1984 paper and ITB chapter[1]
>
> My generated positions are fine for all except about 10 settings, and I
> think that I might have an issue with how I'm generating the various
> matrices which have improper rotations with translation vectors.
>
> I've deduced that a matrix, P, with translation vector, t, multiplied by Q
> and u,  can be represented as (P,t)*(Q,u) = (PQ, Pu + t), and so I assume
> that (P,t)^2 is just (PP, Pt+t).
>
> Following equation 12 from the 1984 paper, I can see that, (for example)
> from space group P4(1)32, one of the generating matrices is (4C, 393), and
> if I follow the above schema, I can generate (4C, 393), (4C, 393)^2, (4C,
> 393)^3, and (4C, 393)^4==(1A,000) (the identity).
> {(-y+1/4, x+3/4, z+1/4), (-x+1/2, -y, -z+1/2), (y+1/4, -x+1/4, z+3/4),
> (x,y,z)}  (see the end for matrices)
>
> I can't get the same cycle when I start with an improper rotation with a
> non-zero translation vector.
>
> For example:
> I3Q999 from Fd-3c. -> Improper rotation of matrix 3Q (z,x,y) with a
> translation vector of (3/4,3/4,3/4)
> From Table 4 in the 1984 paper, I know that this is (-z+3/4, -x+3/4,
> -y+3/4), so the "improper" rotation only affects the signs of the matrix,
> not the translation
>
> But I think I'm missing out something fundamental, as  (I3Q999)^3 !=
> (P1A000)
> eg: {(-z+3/4, -x+3/4, -y+3/4), (y, z, x), (-x+3/4, -y+3/4, -z+3/4)}
>
> I3Q999 = (P,t)
> [  0  0 -1 | 3/4 ]
> [ -1  0  0 | 3/4 ]
> [  0 -1  0 | 3/4 ]
>
> (I3Q999)^2 = I3Q999 * I3Q999 = (P,t)*(P,t) = (PP, Pt + t)
> [ 0 1 0 | 0 ]
> [ 0 0 1 | 0 ]
> [ 1 0 0 | 0 ]
>
> (I3Q999)^3 = I3Q999 * I3Q999 * I3Q999 = (P,t)*(PP, Pt + t) = (PPP, PPt +
> Pt + t)
> [ -1  0  0 | 3/4 ][ 1 0 0 | 0 ]
> [  0 -1  0 | 3/4 ]   !=   [ 0 1 0 | 0 ]
> [  0  0 -1 | 3/4 ][ 0 0 1 | 0 ]
>
>
>
> There aren't any examples of improper transformations in the papers, I
> don't know enough group theory to get enough out of the rest of the
> international tables, and I don't know the notation of Zachariasen [2].
>
> Can anybody help point me in the right direction?
>
>
> Thanks
>
> Matthew Rowles
>
>
> [1] Acta Cryst (1984), A40, 567-571 and International Tables, Vol. B,
> Chapter 1.4
> [2] Theory of X-Ray Diffraction in Crystals (1967), Ch. 2.
>
>
>
> P4C393 = (P,t)
> [ 0 -1  0 | 1/4 ]
> [ 1  0  0 | 3/4 ]
> [ 0  0  1 | 1/4 ]
>
> (P4C393)^2 = (P,t)*(P,t) = (PP, Pt + t)
> [-1  0 0 | 1/2 ]
> [ 0 -1 0 |  0  ]
> [ 0  0 1 | 1/2 ]
>
> (P4C393)^3 = (P,t)*(PP, Pt + t) = (PPP, PPt + Pt + t)
> [  0 1 0 | 1/4 ]
> [ -1 0 0 | 1/4 ]
> [  0 0 1 | 3/4 ]
>
> (P4C393)^4 = (P,t)*(PPP, PPt + Pt + t) = (, PPPt + PPt + Pt + t)
> [ 1 0 0 | 0 ]
> [ 0 1 0 | 0 ]
> [ 0 0 1 | 0 ]
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
>
> ++
> Please do NOT attach files to the whole list  
> 
> Send commands to   eg: HELP as the subject 
> with no body text
> The Rietveld_L list archive is on 
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
> --
> Prof. Dr. Reinhard Neder
> Kristallographie und Strukturphysik
> Universitaet Erlangen
> Staudtststr. 3; 91058 Erlangen
> tel. +49-9131-8525191
> fax  +49-9131-8525182
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
++
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++

Generating space group general positions - issues implementing Shmueli (1984)

[Matthew Rowles]

Hi all

For various reasons, I'm writing some code to generate the general
positions of the space groups. I'm trying to follow the implementation of
Shmueli in their 1984 paper and ITB chapter[1]

My generated positions are fine for all except about 10 settings, and I
think that I might have an issue with how I'm generating the various
matrices which have improper rotations with translation vectors.

I've deduced that a matrix, P, with translation vector, t, multiplied by Q
and u,  can be represented as (P,t)*(Q,u) = (PQ, Pu + t), and so I assume
that (P,t)^2 is just (PP, Pt+t).

Following equation 12 from the 1984 paper, I can see that, (for example)
from space group P4(1)32, one of the generating matrices is (4C, 393), and
if I follow the above schema, I can generate (4C, 393), (4C, 393)^2, (4C,
393)^3, and (4C, 393)^4==(1A,000) (the identity).
{(-y+1/4, x+3/4, z+1/4), (-x+1/2, -y, -z+1/2), (y+1/4, -x+1/4, z+3/4),
(x,y,z)}  (see the end for matrices)

I can't get the same cycle when I start with an improper rotation with a
non-zero translation vector.

For example:
I3Q999 from Fd-3c. -> Improper rotation of matrix 3Q (z,x,y) with a
translation vector of (3/4,3/4,3/4)
>From Table 4 in the 1984 paper, I know that this is (-z+3/4, -x+3/4,
-y+3/4), so the "improper" rotation only affects the signs of the matrix,
not the translation

But I think I'm missing out something fundamental, as  (I3Q999)^3 !=
(P1A000)
eg: {(-z+3/4, -x+3/4, -y+3/4), (y, z, x), (-x+3/4, -y+3/4, -z+3/4)}

I3Q999 = (P,t)
[  0  0 -1 | 3/4 ]
[ -1  0  0 | 3/4 ]
[  0 -1  0 | 3/4 ]

(I3Q999)^2 = I3Q999 * I3Q999 = (P,t)*(P,t) = (PP, Pt + t)
[ 0 1 0 | 0 ]
[ 0 0 1 | 0 ]
[ 1 0 0 | 0 ]

(I3Q999)^3 = I3Q999 * I3Q999 * I3Q999 = (P,t)*(PP, Pt + t) = (PPP, PPt + Pt
+ t)
[ -1  0  0 | 3/4 ][ 1 0 0 | 0 ]
[  0 -1  0 | 3/4 ]   !=   [ 0 1 0 | 0 ]
[  0  0 -1 | 3/4 ][ 0 0 1 | 0 ]



There aren't any examples of improper transformations in the papers, I
don't know enough group theory to get enough out of the rest of the
international tables, and I don't know the notation of Zachariasen [2].

Can anybody help point me in the right direction?


Thanks

Matthew Rowles


[1] Acta Cryst (1984), A40, 567-571 and International Tables, Vol. B,
Chapter 1.4
[2] Theory of X-Ray Diffraction in Crystals (1967), Ch. 2.



P4C393 = (P,t)
[ 0 -1  0 | 1/4 ]
[ 1  0  0 | 3/4 ]
[ 0  0  1 | 1/4 ]

(P4C393)^2 = (P,t)*(P,t) = (PP, Pt + t)
[-1  0 0 | 1/2 ]
[ 0 -1 0 |  0  ]
[ 0  0 1 | 1/2 ]

(P4C393)^3 = (P,t)*(PP, Pt + t) = (PPP, PPt + Pt + t)
[  0 1 0 | 1/4 ]
[ -1 0 0 | 1/4 ]
[  0 0 1 | 3/4 ]

(P4C393)^4 = (P,t)*(PPP, PPt + Pt + t) = (, PPPt + PPt + Pt + t)
[ 1 0 0 | 0 ]
[ 0 1 0 | 0 ]
[ 0 0 1 | 0 ]
++
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++

Call for ideas for additions to the powder diffraction dictionary for CIF

[Matthew Rowles]

Hi all

The CIF dictionaries are going through a revision prior to the second
edition of Volume G of the International Tables being finalised.

As a part of this, the Commission on Powder Diffraction is calling for
suggestions for additions to the powder diffraction dictionary.

If you have any ideas for what data and/or metadata you'd like to record
with your powder data and/or structures derived from powder data, please
let me know, and the CPD will collate these suggestions, and work with you,
the CPD, and the Committee for the Maintenance of the CIF Standard for
potential addition to the powder dictionary.

Any potential changes/additions must by signed off by 31 Dec for inclusion
in the next revision.

Regards

Matthew Rowles

Adjunct Research Fellow, Curtin University
Consultant to the Commission on Powder Diffraction
Technical Specialist (Mineralogy), Intertek
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++

Re: Making a permanent reference sample from SRM 640 or 660?

[Matthew Rowles]

Yes!

Ta a lot for that, Jim.


Matthew

On Tue, 2 Aug 2022 at 21:45, Cline, James P. Dr. (Fed) 
wrote:

> From my Vol H article:
>
>
>
> Mounting of powder specimens for analysis using Bragg-Brentano geometry is
> a non-trivial process that typically requires 20 min to 30 min. The
> objective is to achieve a maximum in packing density of the powder with a
> smooth, flat surface. A 5 μm displacement error in the position of the
> sample surface will have a noticeable impact on the data collected.
> Side-drifted mounts allow for realization of a flat surface with relative
> ease, though maximizing the density of the compact can be challenging.
> Top-mounted specimens can be compacted using a glass plate or bar that
> allows the operator to see the sample surface through the glass and, in
> real time, determine the success or failure in obtaining the desired
> outcome. Some powders, such as that of SRM 640e, “flow” in the mount with
> the oscillation of the glass plate across the sample surface. Others, such
> as SRM 676a do not flow at all; but can be “chopped” into the holder and
> compacted with a single “squish”. Several attempts may be necessary to
> realize a quality mount. A low-wetting-angle, low-viscosity silicone-based
> liquid resin, such as those marketed as vacuum leak sealants in high vacuum
> operations, can be used to infiltrate the compact once mounted; resulting
> in a stable sample that will survive some degree of rough handling.
>
>
>
> This is actually from the J Res NIST version.  The Oxford English
> Dictionary doesn’t approve of the word “squish” for use in sample
> preparation, so it’s not used in the actual Volume H publication.
>
>
>
> Jim
>
>
>
>
>
> James P. Cline
> Materials Measurement Science Division
> National Institute of Standards and Technology
> 100 Bureau Dr. stop 8370 [ B113 / Bldg 217 ]
> Gaithersburg, MD 20899-8523USA
> james.cl...@nist.gov
>
> https://www.nist.gov/people/james-p-cline
> (301) 975 5793
>
>
>
> *From:* rietveld_l-requ...@ill.fr  *On Behalf
> Of *Matthew Rowles
> *Sent:* Monday, August 1, 2022 9:37 PM
> *To:* RIETVELD_L Distribution List 
> *Subject:* Making a permanent reference sample from SRM 640 or 660?
>
>
>
> Hi all
>
>
>
> A while ago, I seem to recall reading a procedure or description on making
> a permanent reference sample from SRM 640 or 660 that involved pressing the
> sample in a specimen holder and then infiltrating with a low-viscosity
> epoxy.
>
>
>
> Does that ring any bells with anyone? Does anyone know of any websites ,
> books, or papers describing such a thing?
>
>
>
> Thanks
>
>
>
> Matthew Rowles
>
>
>
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++

Making a permanent reference sample from SRM 640 or 660?

[Matthew Rowles]

Hi all

A while ago, I seem to recall reading a procedure or description on making
a permanent reference sample from SRM 640 or 660 that involved pressing the
sample in a specimen holder and then infiltrating with a low-viscosity
epoxy.

Does that ring any bells with anyone? Does anyone know of any websites ,
books, or papers describing such a thing?

Thanks

Matthew Rowles
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++

Re: Topas error

[Matthew Rowles]

Hi Davide

I have come across that type of error before, but not in that context (I
think).

Are you able to share your input file/data? I can try on my topas and see
if it works.

Matthew

On Sun, 26 Jun 2022, 15:17 ,  wrote:

> Good morning,
>
> I have got a problem with Topas 5. When I try to load a .imp file with the
> command Auto_T (10) to perform simulated annealing I receive this error
> message :
> access violation at address 78BA2313 in module 'TB_MFC-DLL.DLL'.
> Does anybody know how to resolve this problem?
> Thanks
> Davide
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
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++

Re: Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi Tony

I can't reproduce the certificate values. This is the entire point of my
question.

Matthew

On Fri, 29 Apr 2022, 08:31 iangie,  wrote:

> Dear Mathew,
>
> Understood these values are from the SRM certificate.
> My .pro of the data suggests ~92% alpha, 3% beta, and ~5% Amorphous:
> https://www.dropbox.com/s/r2l4y0iq7d4baj7/ROW.pro?dl=0
> Can you reproduce those values on the certificate?
>
> Cheers!
>
> --
> *Dr. Xiaodong (Tony) Wang*
> *Senior Research Infrastructure Specialist (XRD)*
> Central Analytical Research Facility (CARF)   |  Queensland University of
> Technology
> *Address:* Level 6, P Block, Gardens Point campus, 2 George St Brisbane
> QLD 4000
> *Tel:* +61 7 3138 1904  |   *Mob:* 0452 571 680
> *Email:*   tony .
> w...@qut.edu.au|
>   *Web:* www.qut.edu.au/ife/carf
>
>
> 在 2022-04-27 15:55:28，"Matthew Rowles"  写道：
>
> Yep.
>
> The sample is supposed to contain 87.4 wt% alpha-Si3N4, 3.0 wt% beta-Si3N4
> and 9.6 wt% amorphous.
>
> Matthew
>
> On Tue, 26 Apr 2022 at 20:06, Martin Vickers  wrote:
>
>> Just a point of interest you seem to have a few impurity peaks
>> possibly from Si6N8 (COD entry 96-210-2554 seems to match well). it's not a
>> lot but  you might want to include that phase in your quantitative
>> calculations.
>>
>> Regards,
>>
>> Martin
>>
>>
>> --
>> Martin Vickers
>> Dept. of Chemistry, UCL,
>> 20, Gordon Street
>> WC1H 0AJ
>> 020 7679 5592 (or ex 25592)
>>
>
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++

Re: NIST SRM656 Analysis

[Matthew Rowles]

Yep.

The sample is supposed to contain 87.4 wt% alpha-Si3N4, 3.0 wt% beta-Si3N4
and 9.6 wt% amorphous.

Matthew

On Tue, 26 Apr 2022 at 20:06, Martin Vickers  wrote:

> Just a point of interest you seem to have a few impurity peaks
> possibly from Si6N8 (COD entry 96-210-2554 seems to match well). it's not a
> lot but  you might want to include that phase in your quantitative
> calculations.
>
> Regards,
>
> Martin
>
>
> --
> Martin Vickers
> Dept. of Chemistry, UCL,
> 20, Gordon Street
> WC1H 0AJ
> 020 7679 5592 (or ex 25592)
>
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++

Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi Ed

The beam is smaller than the sample over all angles. - 0.25° divergence at
250 mm radius. I also collected in constant divergence mode, so the
diffracting volume is a constant.

Matthew

On Fri, 15 Apr 2022 at 01:20, Edward Laitila  wrote:

> Just curious, is the sample as prepared in the holder wider than the beam
> width at 10 degrees where you start the scan? This is a common issue that
> not many realize that for quantitative analysis the diffracting volume is
> constant provided the sample is larger than the beam in the tube and
> detector plane. If the beam is larger than the sample at these
> angles you no longer have a constant diffracting volume and hence errors in
> the analysis. I am not sure many of the  manufactures realize this based on
> personal experience with default settings of optics for some
> instruments being much too large. Additionally, background is a major issue
> as I have found especially with amorphous materials present background
> algorithms do not do a very good job and often create the background by
> hand.
>
> Regards,
> Ed
>
> On Tue, Apr 12, 2022 at 5:14 AM Matthew Rowles  wrote:
>
>> Hi all
>>
>> I've collected some more data, and am still getting spurious results, and
>> by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by
>> the external method against SRM 676a.
>>
>> We had some SRM-656alpha (couldn't find any of the beta) stored in a
>> drying oven, and some SRM676a stored in a cupboard. I collected some data
>> using a D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed
>> divergence, 250 mm radius, 2x2.5° sollers). The patterns were collected
>> consecutively (using the same program), with a single peak from SRM1976 (b,
>> I think), acting as an intensity calibrant (the intensity didn't
>> appreciably change), collected before, after, and between.
>>
>> Does anybody want to have a look at the data and see what I'm doing
>> wrong? Data available at:
>>
>> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy
>>
>>
>> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al656.xy
>>
>>
>> Thanks
>>
>> Matthew
>>
>>
>>
>>
>>
>> On Wed, 16 Mar 2022 at 21:13, Matthew Rowles  wrote:
>>
>>> Hi List People
>>>
>>> Do any of you use NIST SRM656 in your quantitative analysis quality
>>> control?
>>>
>>> I've recently started at a new lab, and am finding it impossible to make
>>> a physically realistic model (in Topas) that gives results anywhere near
>>> correct (or at least, close to the certificate values).
>>>
>>> As an example, using the external std approach with SRM676, I've managed
>>> to calculate there is -11 wt% amorphous in the beta-656 standard.
>>>
>>> I've tried using the silicon nitride structures given in the SRM
>>> certificate, but the papers and the ICSD entries don't list any thermal
>>> parameters.
>>>
>>> I can get the same results as given on the certificate using a siroquant
>>> model, but I don't know the provenance of the HKL files used in the
>>> analysis.
>>>
>>>
>>> Thanks in advance
>>>
>>>
>>> Matthew Rowles
>>>
>> ++
>> Please do NOT attach files to the whole list > >
>> Send commands to  eg: HELP as the subject with no body
>> text
>> The Rietveld_L list archive is on
>> http://www.mail-archive.com/rietveld_l@ill.fr/
>> ++
>>
>>
>
> --
> Dr. Edward A. Laitila
> Senior Research Engineer/Scientist II/Adjunct Assistant Professor
> Michigan Technological University
> Dept. of MSE
> Room 628 M Building
> (906) 369-2041
>
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++

Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi Holger

There is a good paper by Ian Madsen, Nikki Scarlett, and Arnt Kern about
the quantification of amorphous materials -
https://doi.org/10.1524/zkri.2011.1437

On the RR, I'll let the CPD know!

Matthew

On Thu, 14 Apr 2022 at 16:51, Holger Kletti 
wrote:

> an actual RR on amourphous contents like thos on crystalline mixtureswould
> really be appriciable, i don't know any publications therewith. The problem
> seems to exist as can be seen here, but also with internal standard method,
> as in personal discussions the question on achieved negative amorphous
> contents (internal as well as external standard method) arises from time to
> time. And not alway this can be solved just by variation of background
> polynoms or other structure related parameters.
>
> So if "anyone" would initiate such a RR i would like to join it 
>
> Holger
> Am 14.04.2022 um 09:49 schrieb Julian Richard Tolchard:
>
> I confess that this discussion seems to validate my personal choice to
> treat Rietveld quantification (and especially amorphous quant) as something
> lying between a quantificational and semi-quantificational technique.
>
>
>
> Has anyone done a proper round-robin on amorphous quant (by any methods
> actually)? There have been some RR’s for crystalline mixtures I know, but I
> can’t remember seeing one for crystalline+amorphous samples.
>
>
>
>
>
> jools
>
>
>
> *From:* rietveld_l-requ...@ill.fr 
>  *On Behalf Of *Matthew Rowles
> *Sent:* torsdag 14. april 2022 09:03
> *To:* Jonathan WRIGHT  
> *Cc:* RIETVELD_L Distribution List  
> *Subject:* Re: NIST SRM656 Analysis
>
>
>
> Hi Jon
>
>
>
> The data is put on an absolute scale through the external standard
> approach. The calculations assume that the QPA for corundum in NIST
> SRSM676a is 99.02 wt%. This scaling factor is then applied to the silicon
> nitride pattern.
>
>
>
> re surface roughness: The samples were backpacked against a glass surface,
> and the powders used as-received. I've never measured the particle size
> distribution of either (any!) SRM, but the certificates describe 676a as
> "fully disaggregated" and "grains are sub-micrometer in size and equi-axial
> in shape" and the 656 certificate has a particle size distribution by laser
> scattering, with 100% less than 5 um. In our other work, we aim to
> micronise to less than 10 um. Our grinding checks show that we get 100 vol%
> <15 um and 95 vol% <6 um.
>
>
>
> I've never used the Pitschke or Suortti roughness corrections available in
> Topas, and have no intuition as to the magnitude of their correction or
> what "proper" values should be.
>
>
>
>
>
> Matthew
>
>
>
>
>
> On Wed, 13 Apr 2022 at 18:11, Jonathan WRIGHT  wrote:
>
> Maybe a silly question: are you assuming you have the data on an absolute
> scale
> in order to do these calculations? Do things like surface roughness
> somehow not
> matter?
>
> Best
>
> Jon
>
>
>
>
> On 13/04/2022 11:56, Matthew Rowles wrote:
> > Thanks Tony
> >
> > When I add the absorption edge correction to the silicon nitride model
> (and add
> > beta-silicon nitride), it becomes -2.8 wt% amorphous; up a little due to
> the
> > added correction and down a little due to the extra phase.
> >
> > If I change your al-SN thermals from 1 to those given in ICSD 77811, I
> get +4.8
> > wt% amorphous. Your atoms were already neutral, so I left them as-is.
> >
> > If I make all the Si-nitride phases' thermal parameters == 0, then I can
> get up
> > to 8.5 wt% amorphous.
> >
> > In all of this, corundum is staying as charged atoms, with Al and O beqs
> fixed
> > at 0.334 and 0.278.
> >
> > I'll have to have a go at applying the absorption edge correction; I
> always
> > forget which parameter is which thing and have to rederive my
> understanding of
> > it everytime...
> >
> >
> > Thanks
> >
> > Matthew
> >
> > On Wed, 13 Apr 2022 at 13:58, iangie  ian...@126.com>> wrote:
> >
> > Dear Matthew,
> >
> > I tried your data and get ~-1% amorphous. My .pro is in below link.
> >
> > https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0
> <https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fwww.dropbox.com%2Fs%2Fxuw13c91l9gq5m5%2FROW.pro%3Fdl%3D0=04%7C01%7Cjulianrichard.tolchard%40sintef.no%7Ced6d59fce55f4454e6a408da1de54221%7Ce1f00f39604145b0b309e0210d8b32af%7C1%7C0%7C637855168216257549%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000=fQatqp0bH0nfkYmTd8bWQkEALCntqGFYj

Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi Jon

The data is put on an absolute scale through the external standard
approach. The calculations assume that the QPA for corundum in NIST
SRSM676a is 99.02 wt%. This scaling factor is then applied to the silicon
nitride pattern.

re surface roughness: The samples were backpacked against a glass surface,
and the powders used as-received. I've never measured the particle size
distribution of either (any!) SRM, but the certificates describe 676a as
"fully disaggregated" and "grains are sub-micrometer in size and equi-axial
in shape" and the 656 certificate has a particle size distribution by laser
scattering, with 100% less than 5 um. In our other work, we aim to
micronise to less than 10 um. Our grinding checks show that we get 100 vol%
<15 um and 95 vol% <6 um.

I've never used the Pitschke or Suortti roughness corrections available in
Topas, and have no intuition as to the magnitude of their correction or
what "proper" values should be.


Matthew


On Wed, 13 Apr 2022 at 18:11, Jonathan WRIGHT  wrote:

> Maybe a silly question: are you assuming you have the data on an absolute
> scale
> in order to do these calculations? Do things like surface roughness
> somehow not
> matter?
>
> Best
>
> Jon
>
>
>
>
> On 13/04/2022 11:56, Matthew Rowles wrote:
> > Thanks Tony
> >
> > When I add the absorption edge correction to the silicon nitride model
> (and add
> > beta-silicon nitride), it becomes -2.8 wt% amorphous; up a little due to
> the
> > added correction and down a little due to the extra phase.
> >
> > If I change your al-SN thermals from 1 to those given in ICSD 77811, I
> get +4.8
> > wt% amorphous. Your atoms were already neutral, so I left them as-is.
> >
> > If I make all the Si-nitride phases' thermal parameters == 0, then I can
> get up
> > to 8.5 wt% amorphous.
> >
> > In all of this, corundum is staying as charged atoms, with Al and O beqs
> fixed
> > at 0.334 and 0.278.
> >
> > I'll have to have a go at applying the absorption edge correction; I
> always
> > forget which parameter is which thing and have to rederive my
> understanding of
> > it everytime...
> >
> >
> > Thanks
> >
> > Matthew
> >
> > On Wed, 13 Apr 2022 at 13:58, iangie  ian...@126.com>> wrote:
> >
> > Dear Matthew,
> >
> > I tried your data and get ~-1% amorphous. My .pro is in below link.
> >
> > https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0
> > <https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0>
> >
> > I normally do not refine Beq, which I believe gives biggest source
> of error
> > in QPA...
> >
> >
> > Cheers!
> >
> > --
> >
> > *Dr. Xiaodong (Tony) Wang*
> > *Senior Research Infrastructure Specialist (XRD)*
> > Central Analytical Research Facility (CARF)   |  Queensland
> University of
> > Technology
> > *Address:* Level 6, P Block, Gardens Point campus, 2 George St
> Brisbane QLD 4000
> > *Tel:*+61 7 3138 1904  | *Mob:*0452 571 680
> > *Email:* tony <mailto:stephen.blank...@qut.edu.au>.
> > <mailto:stephen.blank...@qut.edu.au>w...@qut.edu.au
> > <mailto:stephen.blank...@qut.edu.au>   | *Web:*
> www.qut.edu.au/ife/carf
> > <http://www.qut.edu.au/ife/carf>
> >
> >
> > At 2022-04-13 13:00:44, "Matthew Rowles"  > <mailto:rowle...@gmail.com>> wrote:
> >
> > Hi all
> >
> > Thanks to those that have replied off-list.
> >
> > I've managed to jiggle things around and get various answers. If
> you
> > want an answer between -14 and +6 wt% amorphous, I can make it
> happen. I
> > can either use charged atoms or not, or use thermal parameters
> or not.
> > Combining those between the corundum and Si3N4, you get the
> following:
> >
> >
> > image.png
> > This is using the scattering factors defined with 11 gaussians.
> >
> > If you use the ones defined by 9 gaussians, you get
> > image.png
> >
> > The structures I used are below. In the certificate for 656, the
> > structures are referenced, but those structures have no thermal
> > parameters. Does anyone know what was used in the NIST
> determination?
> >
> >
> >
> > phase_name "Aluminium_oxide_alpha_10425_icsd"
> > Hexagonal( 4.759355, 12.99231)
> > space_group "R -3 c H"
> > 

Re: Re: NIST SRM656 Analysis

[Matthew Rowles]

Thanks Tony

When I add the absorption edge correction to the silicon nitride model (and
add beta-silicon nitride), it becomes -2.8 wt% amorphous; up a little due
to the added correction and down a little due to the extra phase.

If I change your al-SN thermals from 1 to those given in ICSD 77811, I
get +4.8 wt% amorphous. Your atoms were already neutral, so I left them
as-is.

If I make all the Si-nitride phases' thermal parameters == 0, then I can
get up to 8.5 wt% amorphous.

In all of this, corundum is staying as charged atoms, with Al and O beqs
fixed at 0.334 and 0.278.

I'll have to have a go at applying the absorption edge correction; I always
forget which parameter is which thing and have to rederive my understanding
of it everytime...


Thanks

Matthew

On Wed, 13 Apr 2022 at 13:58, iangie  wrote:

> Dear Matthew,
>
> I tried your data and get ~-1% amorphous. My .pro is in below link.
>
> https://www.dropbox.com/s/xuw13c91l9gq5m5/ROW.pro?dl=0
>
> I normally do not refine Beq, which I believe gives biggest source of
> error in QPA...
>
>
> Cheers!
>
> --
> *Dr. Xiaodong (Tony) Wang*
> *Senior Research Infrastructure Specialist (XRD)*
> Central Analytical Research Facility (CARF)   |  Queensland University of
> Technology
> *Address:* Level 6, P Block, Gardens Point campus, 2 George St Brisbane
> QLD 4000
> *Tel:* +61 7 3138 1904  |   *Mob:* 0452 571 680
> *Email:*   tony .
> w...@qut.edu.au|
>   *Web:* www.qut.edu.au/ife/carf
>
>
> At 2022-04-13 13:00:44, "Matthew Rowles"  wrote:
>
> Hi all
>
> Thanks to those that have replied off-list.
>
> I've managed to jiggle things around and get various answers. If you want
> an answer between -14 and +6 wt% amorphous, I can make it happen. I can
> either use charged atoms or not, or use thermal parameters or not.
> Combining those between the corundum and Si3N4, you get the following:
>
>
> [image: image.png]
> This is using the scattering factors defined with 11 gaussians.
>
> If you use the ones defined by 9 gaussians, you get
> [image: image.png]
>
> The structures I used are below. In the certificate for 656, the
> structures are referenced, but those structures have no thermal parameters.
> Does anyone know what was used in the NIST determination?
>
>
>
> phase_name "Aluminium_oxide_alpha_10425_icsd"
> Hexagonal( 4.759355, 12.99231)
> space_group "R -3 c H"
> site Al1 num_posns  12 x 0  y 0 z 0.14772 occ Al+3 1. beq  0.318
> site O1  num_posns  18 x 0.3064 y 0 z 0.25occ O-2  1. beq  0.334
>
> phase_name "ALPHA_Marchand_ICSD_26191"
> Hexagonal( 7.75411, 5.62034)
> space_group "P31c" 'atom positions from Marchand. Thermals from ICSD 77811
> site Si1 num_posns  6 x 0.0806 y 0.5095 z 0.3020 occ Si+4 1   beq 0.25
> site Si2 num_posns  6 x 0.1675 y 0.2560 z 0.0070 occ Si+4 1   beq 0.29
> site N1  num_posns  2 x 0  y 0  z 0  occ N1.  beq 0.88
> site N2  num_posns  2 x =1/3;  y =2/3;  z 0.3500 occ N1.  beq 0.46
> site N3  num_posns  6 x 0.0390 y 0.3860 z 0.0310 occ N1.  beq 1.06
> site N4  num_posns  6 x 0.3190 y 0.3210 z 0.2660 occ N1.  beq 0.17
>
> phase_name "BETA_Billy_ICSD_35566"
> Hexagonal( 7.60633, 2.90778)
> space_group "P 63/m" ' structure from Billy, thermals from ICSD 170004
> site Si1 num_posns  6 x 0.2323 y 0.4096 z 0.25 occ Si+4   1  beq 0.231
> site N1  num_posns  2 x =1/3;  y =2/3;  z 0.25 occ N  1  beq 0.326
> site N2  num_posns  6 x 0.3337 y 0.0323 z 0.25 occ N  1  beq 0.314
>
>
>
>
>
>
> On Tue, 12 Apr 2022 at 17:13, Matthew Rowles  wrote:
>
>> Hi all
>>
>> I've collected some more data, and am still getting spurious results, and
>> by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by
>> the external method against SRM 676a.
>>
>> We had some SRM-656alpha (couldn't find any of the beta) stored in a
>> drying oven, and some SRM676a stored in a cupboard. I collected some data
>> using a D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed
>> divergence, 250 mm radius, 2x2.5° sollers). The patterns were collected
>> consecutively (using the same program), with a single peak from SRM1976 (b,
>> I think), acting as an intensity calibrant (the intensity didn't
>> appreciably change), collected before, after, and between.
>>
>> Does anybody want to have a look at the data and see what I'm doing
>> wrong? Data available at:
>>
>> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy
>>
>>
>> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al6

Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi all

Thanks to those that have replied off-list.

I've managed to jiggle things around and get various answers. If you want
an answer between -14 and +6 wt% amorphous, I can make it happen. I can
either use charged atoms or not, or use thermal parameters or not.
Combining those between the corundum and Si3N4, you get the following:


[image: image.png]
This is using the scattering factors defined with 11 gaussians.

If you use the ones defined by 9 gaussians, you get
[image: image.png]

The structures I used are below. In the certificate for 656, the structures
are referenced, but those structures have no thermal parameters. Does
anyone know what was used in the NIST determination?



phase_name "Aluminium_oxide_alpha_10425_icsd"
Hexagonal( 4.759355, 12.99231)
space_group "R -3 c H"
site Al1 num_posns  12 x 0  y 0 z 0.14772 occ Al+3 1. beq  0.318
site O1  num_posns  18 x 0.3064 y 0 z 0.25occ O-2  1. beq  0.334

phase_name "ALPHA_Marchand_ICSD_26191"
Hexagonal( 7.75411, 5.62034)
space_group "P31c" 'atom positions from Marchand. Thermals from ICSD 77811
site Si1 num_posns  6 x 0.0806 y 0.5095 z 0.3020 occ Si+4 1   beq 0.25
site Si2 num_posns  6 x 0.1675 y 0.2560 z 0.0070 occ Si+4 1   beq 0.29
site N1  num_posns  2 x 0  y 0  z 0  occ N1.  beq 0.88
site N2  num_posns  2 x =1/3;  y =2/3;  z 0.3500 occ N1.  beq 0.46
site N3  num_posns  6 x 0.0390 y 0.3860 z 0.0310 occ N1.  beq 1.06
site N4  num_posns  6 x 0.3190 y 0.3210 z 0.2660 occ N1.  beq 0.17

phase_name "BETA_Billy_ICSD_35566"
Hexagonal( 7.60633, 2.90778)
space_group "P 63/m" ' structure from Billy, thermals from ICSD 170004
site Si1 num_posns  6 x 0.2323 y 0.4096 z 0.25 occ Si+4   1  beq 0.231
site N1  num_posns  2 x =1/3;  y =2/3;  z 0.25 occ N  1  beq 0.326
site N2  num_posns  6 x 0.3337 y 0.0323 z 0.25 occ N      1  beq 0.314






On Tue, 12 Apr 2022 at 17:13, Matthew Rowles  wrote:

> Hi all
>
> I've collected some more data, and am still getting spurious results, and
> by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by
> the external method against SRM 676a.
>
> We had some SRM-656alpha (couldn't find any of the beta) stored in a
> drying oven, and some SRM676a stored in a cupboard. I collected some data
> using a D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed
> divergence, 250 mm radius, 2x2.5° sollers). The patterns were collected
> consecutively (using the same program), with a single peak from SRM1976 (b,
> I think), acting as an intensity calibrant (the intensity didn't
> appreciably change), collected before, after, and between.
>
> Does anybody want to have a look at the data and see what I'm doing wrong?
> Data available at:
>
> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy
>
>
> https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al656.xy
>
>
> Thanks
>
> Matthew
>
>
>
>
>
> On Wed, 16 Mar 2022 at 21:13, Matthew Rowles  wrote:
>
>> Hi List People
>>
>> Do any of you use NIST SRM656 in your quantitative analysis quality
>> control?
>>
>> I've recently started at a new lab, and am finding it impossible to make
>> a physically realistic model (in Topas) that gives results anywhere near
>> correct (or at least, close to the certificate values).
>>
>> As an example, using the external std approach with SRM676, I've managed
>> to calculate there is -11 wt% amorphous in the beta-656 standard.
>>
>> I've tried using the silicon nitride structures given in the SRM
>> certificate, but the papers and the ICSD entries don't list any thermal
>> parameters.
>>
>> I can get the same results as given on the certificate using a siroquant
>> model, but I don't know the provenance of the HKL files used in the
>> analysis.
>>
>>
>> Thanks in advance
>>
>>
>> Matthew Rowles
>>
>
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++

Re: NIST SRM656 Analysis

[Matthew Rowles]

Hi all

I've collected some more data, and am still getting spurious results, and
by spurious, I mean -5 wt% amorphous in SRM-alpha-656 when quantified by
the external method against SRM 676a.

We had some SRM-656alpha (couldn't find any of the beta) stored in a drying
oven, and some SRM676a stored in a cupboard. I collected some data using a
D8 with Ni-filtered Cu and a lynx-eye detector (0.25° fixed divergence, 250
mm radius, 2x2.5° sollers). The patterns were collected
consecutively (using the same program), with a single peak from SRM1976 (b,
I think), acting as an intensity calibrant (the intensity didn't
appreciably change), collected before, after, and between.

Does anybody want to have a look at the data and see what I'm doing wrong?
Data available at:
https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_676a.xy

https://raw.githubusercontent.com/rowlesmr/pdCIFplotter/changing-str-to-float-conversion/data/row_Cu_al656.xy


Thanks

Matthew





On Wed, 16 Mar 2022 at 21:13, Matthew Rowles  wrote:

> Hi List People
>
> Do any of you use NIST SRM656 in your quantitative analysis quality
> control?
>
> I've recently started at a new lab, and am finding it impossible to make a
> physically realistic model (in Topas) that gives results anywhere near
> correct (or at least, close to the certificate values).
>
> As an example, using the external std approach with SRM676, I've managed
> to calculate there is -11 wt% amorphous in the beta-656 standard.
>
> I've tried using the silicon nitride structures given in the SRM
> certificate, but the papers and the ICSD entries don't list any thermal
> parameters.
>
> I can get the same results as given on the certificate using a siroquant
> model, but I don't know the provenance of the HKL files used in the
> analysis.
>
>
> Thanks in advance
>
>
> Matthew Rowles
>
++
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++

NIST SRM656 Analysis

[Matthew Rowles]

Hi List People

Do any of you use NIST SRM656 in your quantitative analysis quality control?

I've recently started at a new lab, and am finding it impossible to make a
physically realistic model (in Topas) that gives results anywhere near
correct (or at least, close to the certificate values).

As an example, using the external std approach with SRM676, I've managed to
calculate there is -11 wt% amorphous in the beta-656 standard.

I've tried using the silicon nitride structures given in the SRM
certificate, but the papers and the ICSD entries don't list any thermal
parameters.

I can get the same results as given on the certificate using a siroquant
model, but I don't know the provenance of the HKL files used in the
analysis.


Thanks in advance


Matthew Rowles
++
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++

Re: Request for help for anyone who happens to have a copy of the AIP volume Neutron Scattering from 1981

[Matthew Rowles]

Hi Martin

I've got access! What do you want?

Matthew

On Thu, 11 Nov 2021 at 10:34, Martin Dove  wrote:

> Hello
>
> Does anyone on this list have a copy of, or easy access to, the 1981 AIP
> Conference Proceedings 89 entitled Neutron Scattering, from a conference in
> 1981.
>
> I can’t get hold of a copy, at least yet not legally, but I would like to
> get hold of three numbers from one paper in this journal.
>
> If anyone can I help I would be most grateful.
>
> Best wishes
>
> Martin Dove++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on
> http://www.mail-archive.com/rietveld_l@ill.fr/
> ++
>
>
++
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++

Re: separation of large from small particles in a powder

[Matthew Rowles]

Hi Jean-Marc

Gravity separation is probably a thing to keep going with, but with heavier
liquids.

There is a program here (CENTRISET -
https://woodshole.er.usgs.gov/openfile/of2005-1001/htmldocs/vbasic_software.htm)
that will help you in calculating settling times for gravity and centrifuge
separation given liquid temperature and viscosity, and particle size and
density.

Note: I have zero experience with this, but it does seem feasible.

Matthew




On Thu, 1 Jul 2021 at 17:21, Jean-Marc Joubert 
wrote:

> Dear all,
> I have another question more or less related to the topic of clay sample
> preparation.
> I would like to separate the coarse from the fine grains in a powder
> obtained by crushing.
> This is in order to get the finest (1 to 5 µm) grains without having to
> introduce too much strain by a too energetic crushing.
> From the SEM analysis this fine particles are indeed present in the powder
> but mixed with larger particles (~30 µm).
> Sieving in this size range is probably not very efficient.
> I considered using settling in alcohol or acetone but the density of the
> materials is very large (~7, it is an intermetallic compound) so that all
> the particles fall very fast to the bottom.
> I wonder if somebody has any advice.
> Thanks in advance.
> /Jean-Marc
>
>
>
>
>
>
> Le 01/07/2021 à 09:30, Kemp, Simon J. a écrit :
>
> Hi Matthew,
>
>
>
> Welcome to the wonderful world of clay mineralogy !
>
>
>
> Separating the clay (typically <2 um) by gravity settling is actually
> preferable to centrifuging, as you can more easily check for flocculation.
> [If this is a problem add some drops of sodium hexametaphosphate (‘Calgon’)
> solution.]  At BGS, we dry our isolated <2 um fractions right down in a
> moisture extraction oven (set at 55degC), homogenise and then resuspend a
> known amount (¬80 mg) to produce a consistently thick oriented mount.
>
>
>
> If you are not aware of it – Moore & Reynolds (1997) is the bible for clay
> preparation and analysis – very easy to follow.
>
>
>
> Moore, D.M. and Reynolds, R.C. 1997*.  X-Ray Diffraction and the
> Identification and Analysis of Clay Minerals, Second Edition.* Oxford
> University Press, New York.
>
>
>
> Best regards, Simon
>
>
>
> *Simon Kemp*
>
> Senior Mineralogist
>
>
>
> *p   *+44 (0)115 936 3448
>
> *e*s...@bgs.ac.uk
> *w   *www.bgs.ac.uk
>
>
>
> British Geological Survey | Nicker Hill | Keyworth | Nottingham NG12 5GG |
> UK
>
>
>
>
>
> Profile <http://www.bgs.ac.uk/staff/profiles/0778.html> | *Twitter
> <https://twitter.com/SimonKempBGS>* | Research Gate
> <https://www.researchgate.net/profile/Simon_Kemp2> | Google Scholar
> <https://scholar.google.co.uk/citations?user=UcipPfUJ=en>
>
>
>
>
>
> *From:* rietveld_l-requ...@ill.fr 
>  *On Behalf Of *Matthew Rowles
> *Sent:* 01 July 2021 05:26
> *To:* RIETVELD_L Distribution List  
> *Subject:* Clay sample preparation
>
>
>
> Hi all
>
> I’m gingerly venturing into clay analysis.
>
> I’ve done previous analyses on pre-separated clay fractions by
> resuspending the clay in a little ethanol and dripping onto a Si wafter to
> make an oriented mount (which is then also successively glycolated and heat
> treated).
>
> I have some upcoming work which will necessitate creating the clay
> fraction.
>
> I don’t have a centrifuge, so I have to separate the clay fraction by
> settling. The USGS methodology looks like a good method to follow:
> https://pubs.usgs.gov/of/2001/of01-041/htmldocs/methods/decant.htm
>
>
> After I’ve suctioned off the clay suspension, what is the best way to get
> at the clay? Leave it settle more? Evaporate the water?
>
> (I’m also in the middle of commissioning a spray-drier, so that will help
> with the random mounts.)
>
> Thanks
>
> Matthew Rowles
> This email and any attachments are intended solely for the use of the
> named recipients. If you are not the intended recipient you must not use,
> disclose, copy or distribute this email or any of its attachments and
> should notify the sender immediately and delete this email from your
> system. UK Research and Innovation (UKRI) has taken every reasonable
> precaution to minimise risk of this email or any attachments containing
> viruses or malware but the recipient should carry out its own virus and
> malware checks before opening the attachments. UKRI does not accept any
> liability for any losses or damages which the recipient may sustain due to
> presence of any viruses. Opinions, conclusions or other information in

Re: Clay sample preparation

[Matthew Rowles]

Ta a lot Simon.

That makes sense, you can see the flocs form, and mitigate immediately.
I've got ovens and wafers, so I'll try the constant mass resuspension.

Our library does have a copy of Moore and Reynolds, but we are in the
middle of a lockdown, and I can't get there!


Thanks

Matthew

On Thu, 1 Jul 2021 at 15:30, Kemp, Simon J.  wrote:

> Hi Matthew,
>
>
>
> Welcome to the wonderful world of clay mineralogy !
>
>
>
> Separating the clay (typically <2 um) by gravity settling is actually
> preferable to centrifuging, as you can more easily check for flocculation.
> [If this is a problem add some drops of sodium hexametaphosphate (‘Calgon’)
> solution.]  At BGS, we dry our isolated <2 um fractions right down in a
> moisture extraction oven (set at 55degC), homogenise and then resuspend a
> known amount (¬80 mg) to produce a consistently thick oriented mount.
>
>
>
> If you are not aware of it – Moore & Reynolds (1997) is the bible for clay
> preparation and analysis – very easy to follow.
>
>
>
> Moore, D.M. and Reynolds, R.C. 1997*.  X-Ray Diffraction and the
> Identification and Analysis of Clay Minerals, Second Edition.* Oxford
> University Press, New York.
>
>
>
> Best regards, Simon
>
>
>
> *Simon Kemp*
>
> Senior Mineralogist
>
>
>
> *p   *+44 (0)115 936 3448
>
> *e*s...@bgs.ac.uk
> *w   *www.bgs.ac.uk
>
>
>
> British Geological Survey | Nicker Hill | Keyworth | Nottingham NG12 5GG |
> UK
>
>
>
>
>
> Profile <http://www.bgs.ac.uk/staff/profiles/0778.html> | *Twitter
> <https://twitter.com/SimonKempBGS>* | Research Gate
> <https://www.researchgate.net/profile/Simon_Kemp2> | Google Scholar
> <https://scholar.google.co.uk/citations?user=UcipPfUJ=en>
>
>
>
>
>
> *From:* rietveld_l-requ...@ill.fr  *On Behalf
> Of *Matthew Rowles
> *Sent:* 01 July 2021 05:26
> *To:* RIETVELD_L Distribution List 
> *Subject:* Clay sample preparation
>
>
>
> Hi all
>
> I’m gingerly venturing into clay analysis.
>
> I’ve done previous analyses on pre-separated clay fractions by
> resuspending the clay in a little ethanol and dripping onto a Si wafter to
> make an oriented mount (which is then also successively glycolated and heat
> treated).
>
> I have some upcoming work which will necessitate creating the clay
> fraction.
>
> I don’t have a centrifuge, so I have to separate the clay fraction by
> settling. The USGS methodology looks like a good method to follow:
> https://pubs.usgs.gov/of/2001/of01-041/htmldocs/methods/decant.htm
>
>
> After I’ve suctioned off the clay suspension, what is the best way to get
> at the clay? Leave it settle more? Evaporate the water?
>
> (I’m also in the middle of commissioning a spray-drier, so that will help
> with the random mounts.)
>
> Thanks
>
> Matthew Rowles
> This email and any attachments are intended solely for the use of the
> named recipients. If you are not the intended recipient you must not use,
> disclose, copy or distribute this email or any of its attachments and
> should notify the sender immediately and delete this email from your
> system. UK Research and Innovation (UKRI) has taken every reasonable
> precaution to minimise risk of this email or any attachments containing
> viruses or malware but the recipient should carry out its own virus and
> malware checks before opening the attachments. UKRI does not accept any
> liability for any losses or damages which the recipient may sustain due to
> presence of any viruses. Opinions, conclusions or other information in this
> message and attachments that are not related directly to UKRI business are
> solely those of the author and do not represent the views of UKRI.
>
++
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++

Clay sample preparation

[Matthew Rowles]

Hi all

I’m gingerly venturing into clay analysis.

I’ve done previous analyses on pre-separated clay fractions by resuspending
the clay in a little ethanol and dripping onto a Si wafter to make an
oriented mount (which is then also successively glycolated and heat
treated).

I have some upcoming work which will necessitate creating the clay fraction.

I don’t have a centrifuge, so I have to separate the clay fraction by
settling. The USGS methodology looks like a good method to follow:
https://pubs.usgs.gov/of/2001/of01-041/htmldocs/methods/decant.htm

After I’ve suctioned off the clay suspension, what is the best way to get
at the clay? Leave it settle more? Evaporate the water?

(I’m also in the middle of commissioning a spray-drier, so that will help
with the random mounts.)

Thanks

Matthew Rowles
++
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The Rietveld_L list archive is on http://www.mail-archive.com/rietveld_l@ill.fr/
++

COD licence terms?

[Matthew Rowles]

Hi all

I'm trying to find the licence that the data on the COD is released under.

On the front page, it says "All data on this site have been placed in the
public domain by the contributors.", but I'm unable to find any actual
licence text or other such statement on the website.

Can anyone help?

Thanks

Matthew
++
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++

Re: RE: Software re-binned PD data

[Matthew Rowles]

Hi Tony

If you want to have a look at what the uncertainties are doing, then try
scanning over a peak a couple of dozen times (maybe with a few different mA
settings on the tube, maybe with some different step times) to collect a
range of different intensities. The standard deviation of the "raw" counts
(not raw CPS) should approximately the square root of the number of counts.
If it is different, then something squirrelly is going on.

Matthew

On Fri, 27 Sep 2019 at 13:46, iangie  wrote:

> Dear Rietvelders,
>
> Thanks for your opinions!
> The "re-binning" of 1D data was done by my measurement software
> automatically, rather than by analysis software.
> The CPS is unchanged after its "re-binning". This means, rather than
> adding counts of neighboring steps, it is *averaging* my data (sum counts
> up then divided by the number of combined bins)!
> I have a feeling what my measurement software doing is not correct...
>
> --
> *Dr. Xiaodong (Tony) Wang*
> *Research Infrastructure Specialist (XRD)*
> Central Analytical Research Facility (CARF)   |   Institute for Future
> Environments
> Queensland University of Technology
>
>
> 在 2019-09-27 10:31:45，alancoe...@bigpond.com 写道：
>
> Hi Tony
>
>
>
> >My I ask is this re-bined data from the measurement software considered
> as "raw data" or "treated data"?
>
>
>
> I’m not sure what is meant by treated data. Almost all neutron data and
> synchrotron data with area detectors are “treated data”.
>
>
>
> If the detector has a slit width in the equatorial plane that is 0.03
> degrees 2Th then it makes little sense using a step size that is less than
> 0.03/2 degrees 2Th. If rebinning is done correctly (see rebin_with_dx_of in
> the Technical Reference) then rebinning is basically collecting redoing the
> experiment with a wider slit.
>
>
>
> In the case of your PSD then the resolution of the PSD would be the
> smallest slit width. If the data has broad features relative to the slit
> width then rebinning (or using a bigger slit width) should not change the
> results. You could simulate all this using TOPAS to see the difference.
> Correct rebinning should not affect parameter errors.
>
>
>
> This is a question that is not simple to answer and if there’s concern
> then:
>
>
>
>1. Simulating data with the small step size and performing a fit
>2. And then rebinning with various slit widths and then fitting
>3. And then comparing parameters errors and parameter values for all
>the refinements should shine light on the area.
>
>
>
> I don’t know where but I feeling is that there should be papers on this.
>
>
>
> Cheers
>
> Alan
>
>
>
>
>
> *From:* rietveld_l-requ...@ill.fr  *On Behalf
> Of *iangie
> *Sent:* Thursday, September 26, 2019 1:40 PM
> *To:* rietveld_l@ill.fr
> *Subject:* Software re-binned PD data
>
>
>
> Dear Rietvelder,
>
>
>
> I hope you are doing well.
>
> It is generally acknolwdged that Rietveld refinement should be performed
> on raw data, without any data processing.
> One of our diffractometer/PSD  scans data at its minimal step size (users
> can see that the step size during scan is much smaller than what was set),
> and upon finishing, the measurement software re-bin the counts to the step
> size what users set (so the data also looks smoother, after re-bin).
> My I ask is this re-bined data from the measurement software considered as
> "raw data" or "treated data"? And can we apply Rietveld refinement on this
> data?
>
>
>
> Any comments are welcome. :)
>
> --
>
> *Dr. Xiaodong (Tony) Wang*
>
> *Research Infrastructure Specialist (XRD)*
>
> Central Analytical Research Facility (CARF)   |   Institute for Future
> Environments
>
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>
> ++
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Re: Simultaneous refinement of multiple atoms sharing same site

[Matthew Rowles]

Our chemical engineers like to make perovskites with about 6 elements in
two sites for their solid state fuel cells...

On Mon, 2 Sep. 2019, 16:15 Le Bail Armel,  wrote:

> If more than 2 atoms sharing the same site, then fire the chemist...
>
> Armel
> ++
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Re: Literature on Rietveld limitations in nano materials

[Matthew Rowles]

We've seen that asymmetric profile in our graphene simulations.

.

How many 1000s of atoms can debussy/discus reasonably deal with?

Matthew

On Thu, 6 Jun. 2019, 19:39 Reinhard Neder,  wrote:

> Dear Mr Girgsdies,
>
> Off hand I am not aware of any critical discussion. Let me add a few
> thoughts though that may help to explain the issues at hand.
>
> A Rietveld program calculates the diffraction pattern as a sum of all
> Bragg reflections. Initially these Bragg peaks are treated as
> infinitesimally sharp points at a fixed 2Theta position. This hold in
> particular for the calculation of the structure factor, which is calculated
> at the corresponding point in reciprocal space for the integer values
> triplet hkl. In a second step these sharp peaks are widened by a profile
> function to describe the experimentally observed broad peaks. The
> broadening of the profile function has components due to the instrumental
> resolution and sample contributions (size and strain).
>
> The Rietveld treatment implicitly assumes perfect translational
> periodicity, as all calculations in reciprocal space are limited to the
> integer Bragg positions. The sample contribution to the broadening is thus
> a bit of an artificial "trick" to get a good/reasonable agreement.
>
> In the actual diffraction experiment the diffraction pattern arises form
> the sum of all secondary waves emitted by all atoms. This sum of all the
> secondary waves is a continuous function in reciprocal space. Only in the
> limit of a perfect infinite crystal will the sum reduce to the Bragg
> positions, and be zero at all other points in reciprocal space.
>
> For a (very) small nanoparticle this sum of the secondary waves will
> naturally "widen" the Bragg positions compared to those of a large crystal.
> If one looks at a point slightly off the Bragg position, one has to keep in
> mind that this diffraction angle differs from that of the integer Bragg
> reflection. As a consequence, the individual atomic form factors and the
> structure factor will differ from the values at the integer Bragg position.
> This difference is not included in the Rietveld algorithm. This difference
> can lead to an asymmetric profile function. This profile may be asymmetric
> enough to have its maximum off the Bragg position and one must be super
> careful not to mistake the location of the maximum intensity of such an
> asymmetric profile with the actual Bragg position. This is described nicely
> in Tchoubar & Drits X-ray Diffraction by disordered lamellar structures.
> There are a bunch of "lovely" papers that do misinterpret this.
>
> The small nanoparticles below 3 nm diameter will add two more
> complications to the situation.
>
> A) The (irregular) surface will likely truncate the average bulk unit cell
> at different positions around the nanoparticle. Thus the Rietveld
> assumption that the crystal consists of identical unit cells is no longer
> absolutely correct. This may change the relative intensities.
>
> B) The surface is bound to be subject to
> distortions/reconstructions/different surface chemistry compared to the
> interior of the nanoparticle and will in many cases cause an appreciable
> strain across the particle, which again is not part of the Rietveld
> algorithm.
>
> All in all I would recommend to calculate the diffraction pattern of such
> small nanoparticles by use of the Debye-Scattering-Equation. This algorithm
> adds up the diffraction pattern from the contribution of all atom (pairs)
> and gives a direct diffraction pattern without the need of a sample related
> profile function. The Debussy program by Antonio Cervellino J.Appl.Cryst
> 48, 2026 (2015) and my own DISCUS program JAC 32, 838 (1999)
> "https://github.com/tproffen/DiffuseCode;
>  are two examples of such
> programs.
>
> The special issue of Acta Crystallographica A72 (2016) has several papers
> related to the Deby-Scattering-Equation, Paolo Scardi and Matteo Leoni have
> written several papers on the sample related profile function.
>
> Sincerely
>
> Reinhard Neder
> Am 06.06.19 um 12:39 schrieb Frank Girgsdies:
>
> Dear fellow Rietvelders,
>
> Could anyone point me to some nice literature which critically discusses
> the limitations of the Rietveld method when it comes to nano-crystalline
> materials (specifically in the 1 to 3 nm range)?
> As far as I'm aware, the core Rietveld literature seems to touch this
> point only in the passing.
>
> Background:
> To the best of my knowledge, Rietveld-derived parameters (like lattice
> constants or domain sizes) should not be trusted as being "physically
> meaningful"  anymore when you fit the powder pattern of a material in the
> few nm range with standard Rietveld tools.
> My naive understanding of this problem is that the physical principles of
> diffraction (or rather the best way to model it) gradually change when you
> go from long-range ordered to medium-/short-range ordered materials.
> 

Re: Occupancy factors for mixed site in TOPAS

[Matthew Rowles]

Hi François

You need to use codewords and equations.

In the sites section of the structure, give the occupancy of one element a
name (eg al_occ), and then for the other atom on the same site, give it an
equation in the codes tab (eg =1-al_occ;)

You would then put min/max limits on the first atom of 0/1, and all should
work.

I'll send you a screen shot off-list, lest I get in trouble for sending
attachments.

Matthew Rowles



On Tue, 19 Feb 2019 at 18:04, François Goutenoire <
francois.gouteno...@univ-lemans.fr> wrote:

> Dear Rietveld users,
>
> One more question ! I am unable to find the way to constraint occupancy
> factor for mixed sites in Topas in GUI mode.
>
> Sorry for this basic question, but I did not find any examples in
> Archives Mailing List / Topas Wiki / or even in the Topas examples
>
> Best whishes, François
>
> --
>
> *
> Pr. Francois GOUTENOIRE
> e-mail: francois.gouteno...@univ-lemans.fr
> Tel: 02.43.83.33.54
> FAX: 02.43.83.35.06
> Skype Entreprise visio conférence
> Département des Oxydes et Fluorures
> Institut des Molécules et des Matériaux du Mans
> IMMM - UMR CNRS 6283
> Université du Maine - Avenue Olivier Messiaen
> F-72085 Le Mans Cedex 9
> FRANCE
>
> *
> Formation Rietveld CNRS 2019
> https://cnrsformation.cnrs.fr/stage.php?stage=19089
> Formation SAXS et Réflectivités pour couches minces et matériaux
> nanostructurés.
> https://cnrsformation.cnrs.fr/stage.php?stage=19093
> Bibliographie
>
> https://scholar.google.fr/citations?hl=fr=qC-lmN4J_op=list_works=1=title
> https://orcid.org/-0001-5339-3002
>
> ++
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Re: getting intensities from multiple powder pattern

[Matthew Rowles]

A second vote for Topas. You can have multiple hkl phases and do a Pawley
refinement. The intensities can be given the same keyword, which forces
them to have the same value. You then refine a scale factor on patterns
2-5, with the 1st one fixed at 1.

Matthew

On 6 June 2018 at 17:02, Norberto Masciocchi <
norberto.mascioc...@uninsubria.it> wrote:

> Hi all
> I have done it in the past by changing the "refine flag" in the intensity
> list of the Pawley refinement with a fake scale factor (one per dataset -
> minus the "0th one")  multiplying the intensity values of each reflection.
> Just use TOPAS in launch mode.
> Norberto
>
> Dear all,
>
>
>
> I would like to obtain integrated intensities from several (up to 5)
> powder patterns that were measured at different temperatures.
>
> My idea is to make fit by Pawley (or Le Bail?) method of all datasets at
> the same time and keep integrated intensities of individual hkls the same
> for all datasets.
>
>
>
> Do you know about some software, that can restrain or even fix integrated
> intensities between refined datasets?
>
>
>
> Thank you in advance,
>
> Jan
>
>
>
> *Ing. Jan Rohlicek, Ph.D.*
>
> *Institute of Physics CAS*
>
> * Cukrovarnicka 10/112 162 00 Prague 6*
>
> *Tel: (+420) 220 318 484*
>
> *Email: rohli...@fzu.cz *
>
>
>
>
> 
>  Mail
> priva di virus. www.avg.com
> 
> <#m_5331402660391734722_DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2>
>
> ++
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> ++
>
>
>
> --
> Norberto Masciocchi
> Professor of Chemistry
> Department of Science and High Technology & To.Sca.Lab.
> University of Insubria
> Via Valleggio, 11
> 22100 Como - Italy
> E-mail: norberto.mascioc...@uninsubria.it
> Tel: +39-031-2386613
> Skype: norberto.masciocchi
> Website: toscalab.uninsubria.it
> Publish in: Chem2 Journal (www.chem2.org)!
>
>
>
> ++
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Re: Si Zero-Background Holder Pattern subtraction in GSASII

[Matthew Rowles]

It may not be giving bragg peaks,  but our zero bkg holder definately has
some structure in the bkg that we need to take into account for some
specimens.


Matthew

On 3 Feb 2018 00:41, "Toby, Brian H."  wrote:

> Have you looked at this: https://subversion.xray.
> aps.anl.gov/pyGSAS/Tutorials/BkgFit/FitBkgTut.htm, but why is your
> zero-background plate giving you peaks? It should be off-cut so that there
> is no Bragg diffraction.
>
> Brian
>
> On Feb 2, 2018, at 10:09 AM, Muir, Caelin Frederick 
> wrote:
>
> Hi all,
> I am performing refinement in GSASII on a pattern that was taken with a Si
> zero-background holder. I am unable to figure out how to subtract/ignore
> the peaks associated with the zero-background holder. Any advice is
> appreciated, thanks in advance.
>
> Best,
> Caelin
> ++
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> ++
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> ++
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Textbook for undergraduate XRD course?

[Matthew Rowles]

Hi all

I've been looking around for a textbook for the course that I run on XRD.
It's a 6 week course, 2 hr lecture + 2 hr lab/tutorial per week.

The focus of the course is to get hands-on with the students, so over the
course of the course, the prepare a (simple) sample, collect data, do phase
ID, and a Rietveld quant analysis.
The theory side of things covers an intro to crystallography, intro to
Powder diffraction, instrument geometry and aberrations, data collection,
structure factors, indexing, and Rietveld.

I've been pulling things together from Cullity, K, Young, Jenkins &
Snyder, and a few others

I've just found this book: Pecharsky, V. K., and P. Y. Zavalij. 2009.
Fundamentals of Powder Diffraction and Structural Characterization of
Materials. 2nd ed: Springer.

It seems pretty good.

Any other suggestions?


Matthew Rowles
PhD
Lecturer | Department of Physics and Astronomy

Curtin University
Tel | +61 8 9266 9069
Fax | +61 8 9266 2377

Email | matthew.row...@curtin.edu.au
Web | http://curtin.edu.au
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IUCr 2017

[Matthew Rowles]

Hi all

Is anyone at the IUCr meeting? It would be good to say hi to people.

Matthew
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Re: Thin film thickness measurements using sample displasment

[Matthew Rowles]

Hi Shay

Not only specimen displacement, but also line broadening and relative
intensities. They will all depend on the layer thickness.

I don't know how well it would work, especially as WC is quite a heavy
absorber, but in principle, it could.

You could also try fixed incident been geometry (asymmetric reflection) and
look at the influence of incident angle on the WC peaks.  That could also
help tie things down. Additionally, the intensity of the substrate peaks
would also depend on the layer thickness.

Some equations for line profiles of thin specimens and intensity
corrections for asymmetric reflection can be found here:
Rowles & Buckley, J. Appl. Cryst. (2017). 50
, 240-
251



Hope this helps.

Matthew



On 8 Feb 2017 00:40, "Shay Tirosh"  wrote:

Dear Rietvelders

Say I had a thin layer of weakly crystalline (WC) material on top of a
crystalline material. Obviously when aligning the sample it brings the
crystalline material below the focal plane.
Is it possible to determine the WC material thickness by using the shift in
2-teta of the substrate?
What are the limitations?
Are there publications that has been utilized this method and tackle the
problems like layer transparency?

Thanks

Shay

-- 
_

Dr. Shay Tirosh
Institute for Nanotechnology & Advanced Materials
Bar Ilan University
Ramat Gan, 52900
Israel
Phone: +972-(0)30-531-7320
Mobile: +972-(0)54-8834533 <+972%2054-883-4533>
Email: stiro...@gmail.com
_

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Re: 2-teta shift due to sample displacement in parallel beam

[Matthew Rowles]

J. Appl. Cryst.  (2003). *36*
, 926-930
https://doi.org/10.1107/S0021889803006757
Use of double GoÈbel mirrors with high-temperature stages for powder
diffraction: a strategy to avoid severe intensity fade
Pamela S. Whitfield

.

and I meant "The only effect that.." I can only blame insomnia and
autocorrect for that faux pas.


On 3 February 2017 at 03:01, Whitfield, Pamela S. 
wrote:

> Many, many, many years ago in a galaxy far away I wrote a paper that
> probably no-one read that had some systematic data on this for a double
> mirror parallel beam system (second mirror as an ‘analyzer’) in flat-plate
> theta-theta geometry. This setup is much more sensitive to displacement
> than most but readily shows the effect on position and intensity.
>
> Hunt around in J.Appl.Cryst. for 2003 and you should be able to find it
> buried under a pile of more interesting papers… ;-)
>
>
>
> Pam
>
>
>
> Dr Pamela Whitfield MRSC CChem
>
> Instrument Scientist – POWGEN
>
> Spallation Neutron Source
>
> Oak Ridge National Laboratory
>
> PO Box 2008, MS-6475
>
> Oak Ridge, TN 37831-6475
>
>  Tel: (865) 235-2605
>
> Fax: (865) 574-6080
>
>
>
> Chair: IUCr Commission on Powder Diffraction
>
>
>
> *From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] *On
> Behalf Of *Nicolich, Jeffrey
> *Sent:* Thursday, February 02, 2017 1:36 PM
> *To:* Shay Tirosh
> *Cc:* rietveld_l@ill.fr
> *Subject:* RE: 2-teta shift due to sample displacement in parallel beam
>
>
>
> Shay,
>
>
>
> The important part is to have a parallel beam analyzer (crystal, parallel
> plate collimator or equivalent). The analyzer will then define the 2-theta
> position, not the sample.
>
>
>
> A more interesting question is regarding the intensities. Sample
> displacement will affect intensities in parallel beam geometry. The
> relationship depends on many factors, e.g. fixed or symmetric incident
> angle, surface roughness, sample transparency, flat plate or capillary, …
>
>
>
>
>
> Jeff
>
>
>
> Jeffrey Nicolich, Ph.D. | Principal Scientist
>
> *GCP Applied Technologies*
>
> 62 Whittemore Avenue | Cambridge, MA 02140 | T +1 617.498.3816
> <(617)%20498-3816> | jeffrey.nicol...@gcpat.com
> 
>
>
> THIS E-MAIL AND ANY ATTACHED FILES ARE CONFIDENTIAL AND MAY BE LEGALLY
> PRIVILEGED. If you are not the addressee, any disclosure, reproduction,
> copying, distribution, or use of this communication is strictly prohibited.
> If you have received this transmission in error please notify the sender
> immediately and then delete this e-mail.
>
>
>
>
>
>
>
>
>
> *From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr
> ] *On Behalf Of *Martin Vickers
> *Sent:* Thursday, February 02, 2017 1:21 PM
> *To:* Shay Tirosh
> *Cc:* rietveld_l@ill.fr
> *Subject:* Re: 2-teta shift due to sample displacement in parallel beam
>
>
>
> Hi, Shay. The sample displacement / peak-position relationship is
> equivalent.
>
>
>
> Martin
>
>
>
> On 2 February 2017 at 15:14, Shay Tirosh  wrote:
>
> Dear Rietvelders
>
>
>
> Does the 2-teta shift due to sample displacement in parallel beam is
> similar to Bragg Brentano mode?
>
> If not then what is the mathematical expression in parallel beam?
>
>
>
> Thanks
>
>
>
> Shay
> --
>
> _
>
>
>
> Dr. Shay Tirosh
>
> Institute for Nanotechnology & Advanced Materials
>
> Bar Ilan University
>
> Ramat Gan, 52900
>
> Israel
> Phone: +972-(0)30-531-7320
>
> Mobile: +972-(0)54-8834533 <+972%2054-883-4533>
>
> Email: stiro...@gmail.com
>
> _
>
>
> ++
> Please do NOT attach files to the whole list  >
> Send commands to  eg: HELP as the subject with no body
> text
> The Rietveld_L list archive is on http://www.mail-archive.com/
> rietveld_l@ill.fr/
> ++
>
>
>
>
>
> --
>
> Martin Vickers
> Dept. of Chemistry, UCL,
> 20, Gordon Street
> WC1H 0AJ
> 020 7679 5592 (or ex 25592)
>
> ++
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> rietveld_l@ill.fr/
> ++
>
>
>
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++

RE: 2-teta shift due to sample displacement in parallel beam

[Matthew Rowles]

The only affect that specimen displacement should have on intensities with
a parallel beam is a diminution sure to the diffracted beam being so far
away that the parallel plate collimator cuts of the beam.

If you don't have any diffracted beam optics, then that won't be an issue,
but then you will have a specimen displacement correction. The exact form
depends on the geometry.

If you are running in fixed incident beam mode, or transmission, then
you'll have other intensity, absorption, and displacement corrections to
worry about.

Have a look at
MR Rowles, IC Madsen
Journal of Applied Crystallography 43 (3), 632-634, 2010
And
Rowles & Buckley. J. Appl. Cryst. (2017). *50
*, 240-251

https://doi.org/10.1107/S160057671785

Matthew


On 3 Feb 2017 02:38, "Nicolich, Jeffrey"  wrote:

Shay,



The important part is to have a parallel beam analyzer (crystal, parallel
plate collimator or equivalent). The analyzer will then define the 2-theta
position, not the sample.



A more interesting question is regarding the intensities. Sample
displacement will affect intensities in parallel beam geometry. The
relationship depends on many factors, e.g. fixed or symmetric incident
angle, surface roughness, sample transparency, flat plate or capillary, …





Jeff



Jeffrey Nicolich, Ph.D. | Principal Scientist

*GCP Applied Technologies*

62 Whittemore Avenue | Cambridge, MA 02140 | T +1 617.498.3816
<(617)%20498-3816> | jeffrey.nicol...@gcpat.com 


THIS E-MAIL AND ANY ATTACHED FILES ARE CONFIDENTIAL AND MAY BE LEGALLY
PRIVILEGED. If you are not the addressee, any disclosure, reproduction,
copying, distribution, or use of this communication is strictly prohibited.
If you have received this transmission in error please notify the sender
immediately and then delete this e-mail.









*From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] *On
Behalf Of *Martin Vickers
*Sent:* Thursday, February 02, 2017 1:21 PM
*To:* Shay Tirosh
*Cc:* rietveld_l@ill.fr
*Subject:* Re: 2-teta shift due to sample displacement in parallel beam



Hi, Shay. The sample displacement / peak-position relationship is
equivalent.



Martin



On 2 February 2017 at 15:14, Shay Tirosh  wrote:

Dear Rietvelders



Does the 2-teta shift due to sample displacement in parallel beam is
similar to Bragg Brentano mode?

If not then what is the mathematical expression in parallel beam?



Thanks



Shay
-- 

_



Dr. Shay Tirosh

Institute for Nanotechnology & Advanced Materials

Bar Ilan University

Ramat Gan, 52900

Israel
Phone: +972-(0)30-531-7320

Mobile: +972-(0)54-8834533 <+972%2054-883-4533>

Email: stiro...@gmail.com

_


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-- 

Martin Vickers
Dept. of Chemistry, UCL,
20, Gordon Street
WC1H 0AJ
020 7679 5592 (or ex 25592)

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Re: Parafocussing definition?

[Matthew Rowles]

K (and also Brentano, upon rereading) say that in order to be focussing,
the sample also needs to be toroidally curved; curved along ACB as well as
be rotated about the axis AB; so it is a little more than the traditional
flat-sample effect


So summarising everyone here, and the papers I've been reading,
parafocussing means "sort of focussing given the constraints of actually
making a physical diffractometer". Also, we have a finite source and
detector size, and that with the dimensions of beam footprint and
goniometer radii that we use mean that it all pretty much works out in the
end.


Matthew

On 2 May 2016 at 20:07, Kern, Arnt <arnt.k...@bruker.com> wrote:

> Matthew,
>
>
>
> I think Klug & Alexander (1974) give a good explanation about the origin
> of the term "parafocusing": 2nd edition, section "parafocusing methods",
> page 222 ff.
>
>
>
> Cheers,
>
>
>
> Arnt
>
>
>
> *From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] *On
> Behalf Of *Eduard E. Levin
> *Sent:* Montag, 2. Mai 2016 13:21
> *To:* Cline, James Dr. (Fed); Matthew Rowles
> *Cc:* rietveld_l@ill.fr
> *Subject:* RE: Parafocussing definition?
>
>
>
> Dear James,
>
> For me too, please, if it would not be much of a trouble.
> Thank you in advance!
>
> Eduard
>
> *On Mon, 2 May 2016 11:09:31 +, Cline, James Dr. (Fed) wrote*
> > Bob Cheary and I developed and presented a workshop several times in the
> 1990's that included a discussion of this issue.  I can send you the notes
> for it if you would like them.
> >
> > Jim
> >
> >
> > James P. Cline
> > Materials Measurement Science Division
> > National Institute of Standards and Technology
> > 100 Bureau Dr. stop 8520 [ B113 / Bldg 217 ]
> > Gaithersburg, MD 20899-8523USA
> > jcl...@nist.gov
> > (301) 975 5793
> > FAX (301) 975 5334
> >
> > *From:* rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] *On
> Behalf Of *Matthew Rowles
> > *Sent:* Monday, May 02, 2016 1:53 AM
> > *To:* RIETVELD_L Distribution List <rietveld_l@ill.fr>
> > *Subject:* Parafocussing definition?
> >
> >
> > Hi all
> >
> >
> >
> > I've been trying to find a good explanation of what parafocussing (wrt
> Bragg-Brentato geometry) actually is, but haven't been able to find one.
> >
> >
> >
> > Klug and Alexander just reference Brentano's papers.
> >
> >
> >
> > "The Basics of Crystallography and Diffraction" 2nd ed say that B-B
> geometry is "semi-focussing" because the sample is flat, and not curved to
> follow the focussing circle (this doesn't sound right to me)
> >
> >
> >
> > Brentano, J Appl. Phys. 17, 420 (1946) says that a ray reflecting off
> the arc defined by ACB where A is the source, C is the centre of the gonio,
> and B is the detector (ie the focussing circle)  is automatically
> parafocussing, because you only can establish the location of the
> crystallites, not their orientation, but then goes on to say that you can
> actually find the orientation, as the lattice plane normal bisects the
> angle ACB.
> >
> >
> >
> > I also haven't been able to find a use of the word "parafocus" outside
> of the diffraction literature, so I can't see how the word is used
> elsewhere.
> >
> >
> >
> > Any ideas?
> >
> >
> >
> >
> >
> > Matthew
>
>
> --
> Open WebMail Project (http://openwebmail.org)
>
++
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++

Parafocussing definition?

[Matthew Rowles]

Hi all

I've been trying to find a good explanation of what parafocussing (wrt
Bragg-Brentato geometry) actually is, but haven't been able to find one.

Klug and Alexander just reference Brentano's papers.

"The Basics of Crystallography and Diffraction" 2nd ed say that B-B
geometry is "semi-focussing" because the sample is flat, and not curved to
follow the focussing circle (this doesn't sound right to me)

Brentano, J Appl. Phys. 17, 420 (1946) says that a ray reflecting off the
arc defined by ACB where A is the source, C is the centre of the gonio, and
B is the detector (ie the focussing circle)  is automatically
parafocussing, because you only can establish the location of the
crystallites, not their orientation, but then goes on to say that you can
actually find the orientation, as the lattice plane normal bisects the
angle ACB.

I also haven't been able to find a use of the word "parafocus" outside of
the diffraction literature, so I can't see how the word is used elsewhere.

Any ideas?


Matthew
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++

Re: Air scatter blocker

[Matthew Rowles]

Hi Robert

Exactly! If installed properly, it doesn't affect anything except the
background. I had a nice spreadsheet setup to give me knife heights vs
divergence vs maximum 2T value to make sure that I don't run into forbidden
teritory.

I dispute your assertion that a knife wouldn't be necessary if the optics
worked properly. As far as I know, the only way to get rid of air scatter
would be to evacuate the beam path.

I'm currently doing some experiments with an old knife setup on a D8, and
I'm getting some funny bumps at low angle, but in my experience with a
newer know setup, that is due to a divergence that is too big. I'll see if
I can put something together.

Matthew
On 30 Jul 2015 2:04 pm, Dr. Robert Möckel r.moec...@hzdr.de wrote:

 Hi Matthew,

 what you mentioned earlier is not completely correct:

 An anti-air scatter (or beam knife) does not only reduce background
 (mainly at low angles), but also cuts intensity at higher 2theta values, if
 not installed correctly. It does not result in a sample displacement error,
 it just cuts intensity as it cuts off the beam like you mentioned.
 This is also an relatively easy issue to modell, I even managed to put it
 into an excel-file to calculate the max. 2theta angle that can be measured
 at a certain knife height and detector length. BGMN handles this properly
 as well. Nowadays, there are even knifes available that move vertically,
 depending on the actual 2theta value.

 In general, a beam knife would not be necessary if the optics worked
 properly, i.e. the optical path is not disturbed or diffracted or
 fluorescence would not be generated somewhere in the beam path. Basing on
 our experience, the main source of these unwanted X-rays are within or
 close to the tube itself, making it hard to suppress it effectively.
 All these things result in some strange background phenomena at low angles
 (bumps/edges...). We discussed these issues with Reinhard Kleeberg and
 others for a while. It seems to be a serious problem in modern devices, as
 we experienced this on our own PANalytical and other (Bruker) devices from
 colleagues.

 Regards,

 Robert



 , 30 Jul 2015 11:53:15 +0800 schrieb Matthew Rowles rowle...@gmail.com:

 Hi Jilin

 You could probably add a note to your input file.

 Not everything you use in your hardware can be either properly modelled,
 or
 influence the pattern significantly. Do you need to model the anti-scatter
 slits? They help reduce background.

 One thing that could happen is that if the knife is set up incorrectly, it
 will cut off the beam, shifting the centroid of diffraction. That may
 mimic
 a sample displacement type error.

 Re your comment about double-digit results. Are you talking about the
 quant
 results given in the GUI? The actual answer is going to be a lot less
 precise than that.


 Matthew









 On 30 July 2015 at 09:19, ji zhang jilin_zhang_hous...@yahoo.ca wrote:



 Matthew

 I was thinking shouldn't we be able to input some parameters to reflect
 this hardware configuration in the program?

 I forgot that I had asked the same question in2007 in this list. Nobody
 seemed to care enough except Dr Bergmann. Then I went to do log analysis,
 and this thing is completely forgotten.

 Currently we have topaz where I can't find a way to circumvent this yet
 or
 to handle this as I called it. I am thinking we may need a copy of bgmn.
 Certainly both give double digit results (albeit not the same) and both
 look accurate.



 Sent from Yahoo Mail for iPhone https://yho.com/footer0

 On Jul 29, 2015, 5:56:41 PM, Matthew Rowles wrote:

 Hi

 What do you mean by handle it?

 If the knife edge is correctly set up, the only thing that should change
 is the background.

 Matthew Rowles
 On 30 Jul 2015 3:04 am, ji zhang jilin_zhang_hous...@yahoo.ca wrote:


 About ten years ago, I was working on a D4 with lynx eye, had to put an
 air scatter blocker 1 or 2 mm above the powder sample. In the
 beginning, I
 had to put simple geometry into the bgmn configuration sav-file until Dr
 Bergmann put a parameter airscatter=#.

 Now I came back to the business with a D8 with lynx eye; is there
 anybody
 here willing to share the experience of handling it in TOPAZ?

 thanks

 Jilin zhang

 Sent from Yahoo Mail for iPhone https://yho.com/footer0

 ++
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 Send commands to lists...@ill.fr eg: HELP as the subject with no body
 text
 The Rietveld_L list archive is on
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 ++




 ---
 Dr. rer. nat. Robert Möckel
 Diplom-Mineraloge
 Helmholtz-Institut Freiberg für Ressourcentechnologie
 Tel.:  +49 (0) 3731 39 2079
 Helmholtz-Zentrum Dresden-Rossendorf
 Halsbrücker Str. 34 | 09599 Freiberg
 http://www.hzdr.de/hif | r.moec...@hzdr.de
 Vorstand: Prof. Dr. Dr. h. c. Roland Sauerbrey | Prof. Dr. Dr. h. c. Peter
 Joehnk | VR 1693 beim

Re:Re: Air scatter blocker

[Matthew Rowles]

Hi Tony!

I knew I had seen something before.

Ta

Mathew
On 30 Jul 2015 10:00 pm, iangie ian...@126.com wrote:

 Dear Friends,

 Below macro was already developed in 10th TOPAS user meeting @ Adelaide:

 TOPAS syntax code for the modified intensity correction and flat specimen
 asymmetry peak shape convolution

  ‘Variable_Divergence_Shape_Correction: v = footprint (EDFL); keh = knife
 edge height

 macro Variable_Divergence_Shape_with_knife_edge(v, keh)
 {one_on_x_conv = If(Th  2*ArcTan(2keh/v), -v^2 Sin(2 Th) Rad/(4 Rs^2), -2
 keh^2 (Cos(Th))^3/Sin(Th) Rad/Rs^2);}

  ‘Variable_Divergence_Intensity_Correction: v = footprint (EDFL); keh =
 knife edge height

 macro Variable_Divergence_Intensity_with_knife_edge(v, keh)

 {scale_pks = If(Th  2*ArcTan(2keh/v), Sin(Th), 2 keh/v Cos(Th));}

 If you use fix divergence slit:

 ‘Fix_Divergence_Shape_Correction: divang = divergence angle (EDFA); keh =
 knife edge height

 macro Fix_Divergence_Shape_with_knife_edge(v, keh)
 {prm v = R divang Deg /Sin(Th);
 one_on_x_conv = If( Rs Sin(divang/2 Deg) / Sin(Th - divang/2 Deg) Tan( (Th
 - divang/2 Deg)  keh, -(Pi/360)/Tan(Th) divang^2, -2 keh^2
 (Cos(Th))^3/Sin(Th) Rad/Rs^2);}

 ‘Fix_Divergence_Intensity_Correction: v = footprint; keh = knife edge
 height

 macro Fix_Divergence_Intensity_with_knife_edge(v, keh)

 {scale_pks = If(Rs Sin(divang/2 Deg) / Sin(Th - divang/2 Deg) Tan( (Th -
 divang/2 Deg)  keh, 1, 2 keh/v Cos(Th));}


 or something similar...


 Cheers!


 --
 Yours Sincerely,
 Dr. Xiaodong(Tony) Wang
 XRD Application Scientist
 Bruker Singapore Pte. Ltd.

 At 2015-07-30 21:29:40, Matthew Rowles rowle...@gmail.com wrote:

 Hi Robert

 Exactly! If installed properly, it doesn't affect anything except the
 background. I had a nice spreadsheet setup to give me knife heights vs
 divergence vs maximum 2T value to make sure that I don't run into forbidden
 teritory.

 I dispute your assertion that a knife wouldn't be necessary if the optics
 worked properly. As far as I know, the only way to get rid of air scatter
 would be to evacuate the beam path.

 I'm currently doing some experiments with an old knife setup on a D8, and
 I'm getting some funny bumps at low angle, but in my experience with a
 newer know setup, that is due to a divergence that is too big. I'll see if
 I can put something together.

 Matthew
 On 30 Jul 2015 2:04 pm, Dr. Robert Möckel r.moec...@hzdr.de wrote:

 Hi Matthew,

 what you mentioned earlier is not completely correct:

 An anti-air scatter (or beam knife) does not only reduce background
 (mainly at low angles), but also cuts intensity at higher 2theta values, if
 not installed correctly. It does not result in a sample displacement error,
 it just cuts intensity as it cuts off the beam like you mentioned.
 This is also an relatively easy issue to modell, I even managed to put it
 into an excel-file to calculate the max. 2theta angle that can be measured
 at a certain knife height and detector length. BGMN handles this properly
 as well. Nowadays, there are even knifes available that move vertically,
 depending on the actual 2theta value.

 In general, a beam knife would not be necessary if the optics worked
 properly, i.e. the optical path is not disturbed or diffracted or
 fluorescence would not be generated somewhere in the beam path. Basing on
 our experience, the main source of these unwanted X-rays are within or
 close to the tube itself, making it hard to suppress it effectively.
 All these things result in some strange background phenomena at low
 angles (bumps/edges...). We discussed these issues with Reinhard Kleeberg
 and others for a while. It seems to be a serious problem in modern devices,
 as we experienced this on our own PANalytical and other (Bruker) devices
 from colleagues.

 Regards,

 Robert



 , 30 Jul 2015 11:53:15 +0800 schrieb Matthew Rowles rowle...@gmail.com:

 Hi Jilin

 You could probably add a note to your input file.

 Not everything you use in your hardware can be either properly modelled,
 or
 influence the pattern significantly. Do you need to model the
 anti-scatter
 slits? They help reduce background.

 One thing that could happen is that if the knife is set up incorrectly,
 it
 will cut off the beam, shifting the centroid of diffraction. That may
 mimic
 a sample displacement type error.

 Re your comment about double-digit results. Are you talking about the
 quant
 results given in the GUI? The actual answer is going to be a lot less
 precise than that.


 Matthew









 On 30 July 2015 at 09:19, ji zhang jilin_zhang_hous...@yahoo.ca wrote:



 Matthew

 I was thinking shouldn't we be able to input some parameters to reflect
 this hardware configuration in the program?

 I forgot that I had asked the same question in2007 in this list. Nobody
 seemed to care enough except Dr Bergmann. Then I went to do log
 analysis,
 and this thing is completely forgotten.

 Currently we have topaz where I can't find a way to circumvent this yet
 or
 to handle

Re: Air scatter blocker

[Matthew Rowles]

Hi

What do you mean by handle it?

If the knife edge is correctly set up, the only thing that should change is
the background.

Matthew Rowles
On 30 Jul 2015 3:04 am, ji zhang jilin_zhang_hous...@yahoo.ca wrote:


 About ten years ago, I was working on a D4 with lynx eye, had to put an
 air scatter blocker 1 or 2 mm above the powder sample. In the beginning, I
 had to put simple geometry into the bgmn configuration sav-file until Dr
 Bergmann put a parameter airscatter=#.

 Now I came back to the business with a D8 with lynx eye; is there anybody
 here willing to share the experience of handling it in TOPAZ?

 thanks

 Jilin zhang

 Sent from Yahoo Mail for iPhone https://yho.com/footer0

 ++
 Please do NOT attach files to the whole list alan.he...@neutronoptics.com
 
 Send commands to lists...@ill.fr eg: HELP as the subject with no body
 text
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 http://www.mail-archive.com/rietveld_l@ill.fr/
 ++



++
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++

Re: source of diamond powder for internal standard

[Matthew Rowles]

Hi Tony

I think we used diamond polishing powder when I was at CSIRO.

Lots of different sizes available.

Matthew
On 19 Jun 2015 3:13 pm, Tony Raftery a.raft...@qut.edu.au wrote:

  Anyone,



 Can someone tell me where to source diamond for use as internal standard.



 It needs to be ‘ideal’ – small particle size ( 1um would be good), narrow
 particle size distribution, elementally pure (which precludes most
 ‘natural’ diamond),  fully crystalline (or near so).



 Please contact me directly though there are others who may be interested.





 regards,

 Tony Raftery

 *Tony Raftery*  |  Laboratory Manager – X-ray  Particles Laboratory
 *Central Analytical Research Facility (IFE)** | Queensland University of
 Technology*

 P Block Podium, Level 6, Room P-628, Gardens Point Campus
 *ph* 3138 5122 | *fax* 3138 4438 | *mobile* 0481 008 595 *email*
 a.raft...@qut.edu.au
 CRICOS No 00213J





 ++
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 text
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 ++



++
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++

Re: Powder Diffraction Discussion Group on Facebook

[Matthew Rowles]

Found the selfie!

'''++'
+#+##+
+##++#
+#
+#
+###+#
+##+#+###+#+++
+##+###+#+
+##+#++++#
+###+###+#
+#+'+'
+++++#+#+'+'++
'###+#+##+#+++'+++
'+##+#+++#+##+++''++#+
'+++'##++++###
'++#####@@###++#@@@#+#
'+#####+++
'+###+#@##@@@+@###@###++++
'##+++###@#+##@@@+#+++
'+++@###+#++##@@@#+'''+'++#@@@##++
'++@@#+;;'+@#+##++
'+#@#+##+#+';;'##@##++
'+###'++#+#'';'##@+#++
'@@#'++#';;##+##++
'+'+'''+'@@@###@###+++#+;;;#@''+'+'+++
'+'''@@@###';;;+##+'++
'+++'@#@#@###+#::;;++@##@#''++
'++'''+''##@@#@##+:::;:++#@#@#'''+'+++
'+++'#@@##'++###;::'+##@@###@#'''+
'#@###'''+##;;;''+#@@@##@#'''+
'@'';;;:;:,,,::'+@@@#+''++
'@#@#+'';:,,:::'+@@@#''+++
'''+#+'';::::::,,:::;;;'+##@#'
'''+#+';;::,,:,,,:::#+###+
'+#+@''+'';;:::;;'++';;;'+###+
;'++@'+'';;+++##++;;:###++##++''+'
;''+#+'+'+';:::+++'''+;;+@@'#++###+'+'
;'''++++'''@@#@''++#+';;'+##@+#+''
;'';'+'#;#@+##++,,+;'+#'##+@+++';;++''++''
;'+#'+;#++'''+'':,:';'''+''+++;'@@#;''
;'';;;#+'+;;''';:::+;;';;+::;;;++;;;@#+'''
;''';'#+';';;''';;';::::;:::;;''::':+@;'''
;'';;;#+';';;';;;;:;;;'':;;:#'
;;;''';;;';;:;,:;''':';;';
;';''';;';;;:::;::;;:,,,;''';;;#';;'''
;''''';;:::';:;::,:;;:,,::;;;''';;;#''
;''''''#'';'#'::';;;;''':;'#;;
;;;;''';;;+;;''::;::;;#';;;'''
;''';;''';;::;;;''';;'
;'';;''';';;:;:::;::;:;;'''@##;;;'
;':::''';';;:;:;'''###+'';
;';;;;'';';'';;;'''';;
;;'';';';;;''';'+;;;'''#+:::;;
;:'';'''##+++';;'';@##++';
::;';;;;:;;''';###'';;
;;:'';';';'';;;''';##':::;
:::''';+;';';';###':::
;;;:::,,''';;';;'''##+;;;;
;;;:+;;;''';;:::;;
:;:,,+''';;:::';'';',;
:;;;::,,,;''';;::;;';,:::;
:;;;,,';;''+';;';:
:;;,'';;'++';;;':.,;;;

RE: regress in crystallographic good practices and knowledge

[Matthew Rowles]

Hi Kurt

Maybe the paper by Bridget Ingham would be of interest: Statistical
measures of spotiness in diffraction rings.

Just an idea.

Matthew
Hi all,

In my defense, 10 of the 12 messages relating to this topic have had their
footers attached.  I will try to figure out how to get rid of it for next
time.

Here is a topic I am interested in: we are collecting a lot of data on an
imaging plate (GSECARS and HPCAT at Advanced Photon Source).  We are
interested in splitting of peaks in some of the samples.  The splitting is
very difficult to see on the integrated pattern, but very easy to see on
the 2-D imaging plate frame itself.  The rings are spotty and it's very
easy to tell which spots are in which ring when the peak is slightly split.

My question is whether there is software I can use to take advantage of
this and fit the spots so I can get a better resolution of the
splitting.  Something in between powder and single crystal.

Thank you,

- Kurt

-Original Message-
From: Larry Finger [mailto:larry.fin...@gmail.com] On Behalf Of Larry Finger
Sent: Friday, May 08, 2015 9:58 AM
To: Kurt Leinenweber; Alan Hewat; Leopoldo Suescun
Cc: rietveld_l@ill.fr
Subject: Re: regress in crystallographic good practices and knowledge

On 05/08/2015 11:16 AM, Kurt Leinenweber wrote:
 Hi Alan,

 I still like the Rietveld list and do read all the posts.

 Is it possible to block attachments so that people can’t attach files any
more?

 -Kurt

Thus writes the guy whose mailer blindly attaches a message footer rather
than in-lining a signature. :)

Although I no longer practice crystallography, and no longer read the
literature, I do find the discussions here of interest. At least I can
follow how little crystallography the average solid-state researcher
actually knows.
Sad to know that bugs in a few programs could completely derail the
science. All the greats of the early part of the 20th century must be
really spinning in their graves!

Larry


++
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Send commands to lists...@ill.fr eg: HELP as the subject with no body text
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++
++
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++

Re: Does analysis done in Bragg Brentano geometry holds for other geometries?

[Matthew Rowles]

With regards grazing incidence, it also depends on the diffracted beam
optics, but it does hold, after correcting for instrumental effects.

have a look at one of my papers
http://dx.doi.org/10.1107/S0021889810007673
On 18/07/2014 4:21 AM, Łukasz Kruszewski lkruszew...@twarda.pan.pl wrote:

 Hi.

 The XRD profile (spectrum) does not only depend on the geometry type, but
 also width of both slits (primary divergence and secondary anti-scatter),
 symmetric (the same at the primary and secondary part) or non-symmetric
 solers, the use of any additional optical elements (e.g., we use radial
 soler instead of the secondary slit), type of detector (the detector
 slit of the zero-dimensional detector does not have the same physical
 meaning as the corresponding window of the position-sensitive detector).
 You cannot hold the B-B geometry in the reflection mode when you go to
 transmission mode - that is why the second one is used to observe
 reflections that are not seen (or barely seen) in the previous mode. Peak
 shape, including its width, would - in some cases - also be different, but
 peak intensity would especially be affected (in many cases).

 I would use LaB6 and silicon standards (of NIST SRM) instead of
 corrections to check the geometry.

 I'm not an expert in terms of grazing incidence, but I'm pretty sure that
 is gives much different information, as this is more textural information.

  Dear Rietvelders
 
 
 
  Does analysis done in Bragg Brentano geometry holds for other geometries
  and XRD techniques providing one have diffracted peaks?
 
  Are there corrections needed to apply between methods.
 
  Say Sheher formula. Dose it holds for peaks reflecting using in-plan
  grazing incident reflections experiment or it needs to be corrected?
 
 
  Thank you from advance
 
  Shay
 
  --
  _
 
  Dr. Shay Tirosh
  Institute for Nanotechnology  Advanced Materials
  Bar Ilan University
  Ramat Gan, 52900
  Israel
  Phone: +972-(0)30-531-7320
  Mobile: +972-(0)54-8834533
  Email: stiro...@gmail.com
  _
 


 --
 Łukasz Kruszewski, Ph.D., adjunct
 Polish Academy of Sciences
 Institute of Geological Sciences
 X-Ray Diffraction Laboratory (coordinator)
 Twarda 51/55 str.
 00-818 Warsaw
 Poland

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 ++



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++

Zero background holders

[Matthew Rowles]

I hope this topic is ok.

Is the Gem Dugout still operational? I'm pricing some zero background
holders for my lab.

If they aren't, are here're any other suppliers of note?

Thanks



Matthew
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++

Re: PO corrections in trigonal space groups?

[Matthew Rowles]

Ta a lot for that Reinhard.

I'll have a read of the paper and see what I can do. I need to read more on
spherical harmonics as well, as they seem a little like magic to me at the
moment.

I agree that the best way is to avoid PO in the first place, but (at least
in this instance) it wasn't in my control.


Thanks


Matthew

On Wednesday, 26 March 2014, Reinhard Kleeberg 
kleeb...@mineral.tu-freiberg.de wrote:

  Dear Matthew,
 in my knowledge, for calcite the {104} in the usual cell choice for
 hexagonal axes is equivalent to {10-11} in rhombohedral axes setting.
 Morphologically, this shape is called by mineralogists the main
 rhombohedra and the six faces belonging to {104} are indeed the directions
 of the perfect cleavage. Thus, the shape of calcite particles
 crushed/milled from bigger crystals are nearly perfect rhombohedra (btw a
 typical exercise used in undergraduate mineralogy classes for demonstrating
 cleavage).
 In common powder sample preparation, you can expect preferred orientation
 of these planes parallel to the sample surface. For Bragg-Brentano geometry
 (rotational symmetric, observation direction perpendicular to the sample
 surface), you need any function fulfilling the symmetry of the Laue class
 for the description of the relative polar-axis density of the hkl oriented
 parallel to the sample surface. This is realized by symmetrized spherical
 harmonics as introduced by Järvinen et al. (1970), Popa (1992), Järvinen
 (1993, 1998). This and similar approaches are included in many Rietveld
 programs, e.g. GSAS, TOPAS, BGMN, MAUD, DDM (?)...

 Back to calcite: You can see an example of a practically working
 correction function in fig. 1c of

 Bergmann, J., Monecke, T., Kleeberg, R. (2001) Alternative algorithm for
 the correction of preferred orientation in Rietveld analysis. J. Appl.
 Cryst. 34, 16-19.
 This function has maxima in the direction of the {104} normal vectors. As
 Leonid wrote, the description of such a rhombohedral symmetry is not
 possible by any uniaxial function like March-Dollase related to one special
 hkl. So there is no way around to choose a more complicated model than the
 March-Dollase.

 However, keep in mind that all these models like spherical harmonics have
 no real physical meaning and are limited in their application. They can
 effectively describe the PO only for rotational symmetry of your
 diffraction experiment, only up to a certain (weak) degree of PO, and only
 if there is a homogeneous PO in your powder sample. So the application of
 any PO correction models in Rietveld analysis is a potential source of
 errors and just the second-best solution. The best is always an optimized
 preparation for a randomly oriented powder mount.

 Reinhard

 Am 26/03/2014 05:46, schrieb Leonid Solovyov:

 Dear Mathew,

 The 104 plane in calcite corresponds to the most intense reflection that is 
 related, in turn, to the best spacing or separation between atomic 
 layers along which the cleavage may occur. This is not a strict rule, of 
 course, as real cleavage planes may be different depending on specific 
 interatomic interactions in the crystal and other aspects, but it works in 
 many cases.
 Note also, that the 104 plane in the hexagonal setting has several 
 symmetry-equivalents, while most Rietveld programs normally generate only one 
 equivalent hkl for each diffraction peak, which makes the uniaxial 
 March-Dollase PO correction invalid for such peculiar directions. This 
 problem is resolved in DDM, where I included a special expanded-hkl option to 
 generate all equivalent hkl's for every peak. About other programs I'm not 
 sure.

 Best regards,
 Leonid
 ***
 Leonid A. Solovyov
 Institute of Chemistry and Chemical Technology
 660036, Akademgorodok 50/24, Krasnoyarsk, Russiasolovyovleonid 
 http://sites.google.com/site/solovyovleonid
 ***


 
 From: Matthew Rowles rowle...@gmail.com 
 javascript:_e(%7B%7D,'cvml','rowle...@gmail.com');
 To: Sitepu, Husinsyah husinsyah.sit...@aramco.com 
 javascript:_e(%7B%7D,'cvml','husinsyah.sit...@aramco.com');
 Cc: daniel.chateig...@ensicaen.fr 
 javascript:_e(%7B%7D,'cvml','daniel.chateig...@ensicaen.fr'); 
 daniel.chateig...@ensicaen.fr 
 javascript:_e(%7B%7D,'cvml','daniel.chateig...@ensicaen.fr');; 
 rietveld_l@ill.fr javascript:_e(%7B%7D,'cvml','rietveld_l@ill.fr'); 
 rietveld_l@ill.fr javascript:_e(%7B%7D,'cvml','rietveld_l@ill.fr');
 Sent: Wednesday, March 26, 2014 8:16 AM
 Subject: Re: PO corrections in trigonal space groups?



 Thanks for your replies.

 Husin, is there any justification for the use of the 104 direction in 
 calcite, other than this is the direction that works? I'm all for doing it if 
 it works, but I'd like a little theoretical backup.

 Thanks Daniel. I'll put something together for a look-see. What corrections 
 are being used in Maud? Are there any

PO corrections in trigonal space groups?

[Matthew Rowles]

Hi all

I have a sample containing a fraction of calcite. My research tells me that
calcite cleaves on {10-11}.

How can I express this as an hkl for the March-Dollase PO correction?

By inspection, {104} is the direction that orients. Is that correct? How
can I derive that?


Thanks


Matthew Rowles
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Send commands to lists...@ill.fr eg: HELP as the subject with no body text
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Re: PO corrections in trigonal space groups?

[Matthew Rowles]

Thanks for your replies.

Husin, is there any justification for the use of the 104 direction in
calcite, other than this is the direction that works? I'm all for doing it
if it works, but I'd like a little theoretical backup.

Thanks Daniel. I'll put something together for a look-see. What corrections
are being used in Maud? Are there any papers on them?

THanks

Matthew


On 25 March 2014 22:32, Sitepu, Husinsyah husinsyah.sit...@aramco.comwrote:

  Dear Matthew,



 Following to Professor Daniel Chateigner 's email, I would like to
 highlight briefly that the preferred orientation (PO) directions for
 calcite (CaCO3) that we used during the refinement using GSAS were

 · 104 for X-ray diffraction data, and

 · 001 for neutron diffraction data.

 Please see the Curtin Library 
 linkhttp://espace.library.curtin.edu.au/R?func=dbin-jump-fullobject_id=10543or
  IUCr Journal of Applied Crystallography, Volume
 35, Part 2 (April 
 2002)http://journals.iucr.org/j/issues/2002/02/00/issconts.html and
 Volume 38, Part 1 (February 
 2005)http://journals.iucr.org/j/issues/2002/02/00/issconts.htmlfor the 
 details.



 With best wishes,



 Husin

 ___

 *Husin Sitepu, PhD*

 SAUDI ARAMCO

 RESEARCH  DEVELOPMENT CENTER

 Dhahran, PO Box 31311, KSA

 Phone: *+966* *876-3050*

 Email: sitep...@aramco.com


 http://scholar.google.com/citations?hl=enuser=cUTV8HkJview_op=list_workspagesize=100


 ___





 -Original Message-
 From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On
 Behalf Of daniel Chateigner
 Sent: Tuesday, March 25, 2014 2:10 PM
 To: rietveld_l@ill.fr
 Subject: Re: PO corrections in trigonal space groups?



 Hi Matthew,



 You would perhaps prefer physically meaningfull PO correction using
 standard functions, at disposal in Maud. If you can give me an ascii double
 column of your data I'll give it a trial.



 daniel



 Le 25/03/2014 11:43, Matthew Rowles a écrit :

  Hi all

 

  I have a sample containing a fraction of calcite. My research tells me

  that calcite cleaves on {10-11}.

 

  How can I express this as an hkl for the March-Dollase PO correction?

 

  By inspection, {104} is the direction that orients. Is that correct?

  How can I derive that?

 

 

  Thanks

 

 

  Matthew Rowles



 --

 http://www.ecole.ensicaen.fr/~chateign/danielc/



 Address:

 IUT-Caen Université de Caen Basse-Normandie and CRISMAT-ENSICAEN

 6 Bd. M. Juin, 14050 Caen



 The Crystallography Open Database: www.crystallography.net The Materials
 Property Open Database: http://www.materialproperties.org/

 Combined Analysis using rays:
 http://iste.co.uk/index.php?f=xACTION=Viewid=359



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Re: N Beta in TOPAS Full Axial Model

[Matthew Rowles]

From the Tech Ref:
[axial_n_beta #20]: Define the number of rays emanating from a point X-ray
source in
the axial plane. Larger values for axial_n_beta increases both accuracy and
calculation time.

Looks like Alan is doing some sort of ray tracing to calculate the peak
profiles.


On 20 December 2013 09:18, Allen, Douglas R. douglas_al...@fmi.com wrote:

  Can anyone tell me the meaning and possible setting for the “N Beta”
 item in the Full Axial Model on the Instrument Parmeters page of TOPAS.  We
 have always used a setting of 20 but I have no idea why or what it means.

 ++
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