Dear All,
The biennial Powder Diffraction & Rietveld Refinement School at Durham
University will take place 29th March-2nd April 2020.
The information about the School content and format, practical information
(deadlines and fees) and the application link are available at:
h
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School at Durham
University will take place 8-12th April 2018.
The applications deadline is approaching - online applications can be submitted
until the end of next week, 19 January 2018, at the School web
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School at Durham
University will take place 8-12th April 2018.
As in previous years, we will offer a combination of lectures covering the
theoretical aspects of powder diffraction and Rietveld refinement,
classroom-based &quo
We are pleased to announce that the third annual "Modern Methods in Rietveld
Refinement for Structural Analysis" school will be held from June 18-23, 2017,
at Oak Ridge National Laboratory in close partnership with the Shull-Wollan
Center Joint Institute for Neutron Sciences (Uni
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School at Durham
University will take place 10-14th April 2016.
As in previous years, we will offer a combination of lectures covering the
theoretical aspects of powder diffraction and Rietveld refinement,
classroom-based
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School at Durham
University will take place 10-14th April 2016.
As in previous years, we will offer a combination of lectures covering the
theoretical aspects of powder diffraction and Rietveld refinement,
classroom-based
p...@aramco.com>
http://scholar.google.com/citations?hl=en&user=cUTV8HkJ&view_op=list_works&pagesize=100
From: alan.he...@gmail.com [mailto:alan.he...@gmail.com] On Behalf Of Alan Hewat
Sent: Wednesday, July 16, 2014 9:43 AM
To: rietveld_l@ill.fr
Subject: Re: information f
PM
Subject:Quantification and rietveld refinement
Sent by:rietveld_l-requ...@ill.fr
Dear rietvelds
I have some samples, all with the same two phases: alumina and crocoite
(PbCrO4) (electrochemical bath). I use Cobalt radiation. Indexing, I use
always the same two ICDD files, 74-0323 for alum
: Friday, September 05, 2014 12:44 PM
To: rietveld_l@ill.fr
Subject: Quantification and rietveld refinement
Dear rietvelds
I have some samples, all with the same two phases: alumina and crocoite
(PbCrO4) (electrochemical bath). I use Cobalt radiation. Indexing, I use always
the same two ICDD
set of educational material on Rietveld refinement using
GSAS+EXPGUI at the APS-11BM site
(http://www.aps.anl.gov/Xray_Science_Division/Powder_Diffraction_Crystallography/)
and additional resources at http://11bm.xray.aps.anl.gov/resources.html.
If you don´t have experience with Rietveld analysis and
Prezado Nelson,
You can find CIF files for both alumina and crocoite phases at the
Crystallography Open Database (www.crystallography.net) looking for
chemical elements.
An excellent set of educational material on Rietveld refinement using
GSAS+EXPGUI at the APS-11BM site (
http
semiquantification
of software for know the quantification of each phase betwen the samples.
Wuhere i can find the right cif files for this two phases, for introduce in
High score plus and made Rietveld refinement.
Where i can find a manual or exemples of how to make a rietveld refinement
of this XRD.
I
> Im student researcher I need a guidelines for refinement structure
double perovskite
> using fullprof or other software in case to reduce Factors and than draw
structures
Dear Colleague.
It is difficult to reply to such a general query. You could start by
reading the FullProf manual and tutori
Dear Rietvelders,
I would like to bring to your attention the following satellite meeting of
the IUCr congress in Montreal.
Rietveld refinement for beginners: bring your data!
Location
InterContinental Montréal
360 Rue Saint Antoine Ouest, Montreal, QC H2Y 3X4, Canada
Date
August 4th, 2014
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School will take place at
Durham University, 30th March - 3rd April March 2014.
As in previous years, the course will offer a combination of lectures covering
the theoretical aspects of powder diffraction and Rietveld refine
Dear All,
The biennial Powder Diffraction & Rietveld Refinement School will take place at
Durham University, 30th March - 3rd April March 2014.
As in previous years, the course will offer a combination of lectures covering
the theoretical aspects of powder diffraction and Rietveld refine
Dear All,
Just a reminder of the approaching applications deadline (31st December)
for the Powder Diffraction and Rietveld Refinement School in Durham, UK.
The EPSRC/IUCr/PCG-SCMP supported biennial Powder Diffraction and
Rietveld Refinement School will take place at Durham University, 18th
Patrick,
>
>
> From: Patrick Price [patrickpric...@gmail.com]
> Sent: Friday, December 04, 2009 6:30 AM
> To: Rietveld_l@ill.fr
> Subject: Rietveld refinement in TOPAS with parallel beam geometry
>
> Since this is my first post I will start with a brief introduct
Patrick,
From: Patrick Price [patrickpric...@gmail.com]
Sent: Friday, December 04, 2009 6:30 AM
To: Rietveld_l@ill.fr
Subject: Rietveld refinement in TOPAS with parallel beam geometry
Since this is my first post I will start with a brief introduction. My
Rietveld refinement
techniques.
I have recently taken a scan of the NIST line profile 660 LaB6
standard followed by scans of my perovskite powders using a step size
of 0.02 degrees and scan time of 4 seconds.
Most of the articles I have read are specific to convergent/divergent
beam geometries and I do
Dear All,
The EPSRC/IUCr/PCG-SCMP supported biennial Powder Diffraction and
Rietveld Refinement School will take place at Durham University, 18th -
22nd April 2010. The course will offer a combination of lectures
covering the theoretical aspects of powder diffraction and Rietveld
refinement
***
--- On Mon, 7/27/09, Nicolae Popa wrote:
> From: Nicolae Popa
> Subject: Re: LP factor in the Rietveld refinement
> To: "Leonid Solovyov" , rietveld_l@ill.fr
> Date: Monday, July 27, 2009, 11:04 AM
> Right, but specially for students-
> beginne
Right, but specially for students- beginners we must be much, let say,
didactic
LP means (Lorentz) * (Polarisation)
What is important in Rietveld refinement when a lot of mirrors &
monochromators are present is how they change (Polarization)
because (Lorentz) is changed by adding fac
/l_solovyov
***
--- On Sun, 7/26/09, Peter Y. Zavalij wrote:
> From: Peter Y. Zavalij
> Subject: RE: LP factor in the Rietveld refinement
> To: rietveld_l@ill.fr
> Date: Sunday, July 26, 2009, 5:03 AM
> That's right. LP refineme
c: rietveld_l@ill.fr
Subject: Re: LP factor in the Rietveld refinement
In this context:
What about the LP for a Goebel mirror followed by a 4-bounce or 2-bounce
primary monochromator?
Best regards
angel l. ortiz
>
> As far as I know, for X-ray mirrors the LP angl
etveld_l@ill.fr
Subject: Re: LP factor in the Rietveld refinement
In this context:
What about the LP for a Goebel mirror followed by a 4-bounce or 2-bounce
primary monochromator?
Best regards
angel l. ortiz
>
> As far as I know, for X-ray mirrors the LP angle is
09, chu...@hkusua.hku.hk wrote:
>
>> From: chu...@hkusua.hku.hk
>> Subject: Re: LP factor in the Rietveld refinement
>> To: "Ross H Colman"
>> Cc: rietveld_l@ill.fr
>> Date: Saturday, July 25, 2009, 4:16 AM
>> Dear Ross,
>>
>>
/l_solovyov
***
--- On Sat, 7/25/09, chu...@hkusua.hku.hk wrote:
> From: chu...@hkusua.hku.hk
> Subject: Re: LP factor in the Rietveld refinement
> To: "Ross H Colman"
> Cc: rietveld_l@ill.fr
> Date: Saturday, July 25,
Dear Ross,
How about the LP factor/monochromator angle if using Gobel mirror in
my D8 system?
Thanks!
stephen
- Message from ucca...@ucl.ac.uk -
Date: Thu, 23 Jul 2009 09:52:55 +0100
From: Ross H Colman
Reply-To: Ross H Colman
Subject: Re: LP factor in the Rietveld
***
--- On Thu, 7/23/09, David Lee wrote:
> From: David Lee
> Subject: Re: AW: LP factor in the Rietveld refinement
> To: "Reitveld"
> Date: Thursday, July 23, 2009, 2:19 PM
> I have a question about the surface
> roughness. The LaB6 po
--Ursprüngliche Nachricht-
Von: Peter Y. Zavalij [mailto:pzava...@umd.edu]
Gesendet: Donnerstag, 23. Juli 2009 05:52
An: rietveld_l@ill.fr
Betreff: RE: LP factor in the Rietveld refinement
Well... the situation with LP is not so simple. Using TOPAS for
refinement
data collected on D8 advance wit
the case
for the LaB6 measurement mentioned by Peter.
Greetings
Bernd
-Ursprüngliche Nachricht-
Von: Peter Y. Zavalij [mailto:pzava...@umd.edu]
Gesendet: Donnerstag, 23. Juli 2009 05:52
An: rietveld_l@ill.fr
Betreff: RE: LP factor in the Rietveld refinement
Well... the situation with
Dear all,
Just to be complete, the Topas technical reference manual also gives the
LP values for a few other common monchromators:
Pg109
"Values for most common monochromators (Cu radiation) are:
Ge : 27.3
Graphite : 26.4
Quartz : 26.6"
Regards
Ross Colman
Ross
ct: RE: LP factor in the Rietveld refinement
> To: "Leonid Solovyov"
> Cc: rietveld_l@ill.fr
> Date: Thursday, July 23, 2009, 7:00 AM
> Dear All,
>
> In this scenario, which should be the number for LP in
> Topas if ones has a
> D8 with a primary monochromator
*
>
> --- On Thu, 7/23/09, Peter Y. Zavalij wrote:
>
> From: Peter Y. Zavalij
> Subject: RE: LP factor in the Rietveld refinement
> To: rietveld_l@ill.fr
> Date: Thursday, July 23, 2009, 4:52 AM
>
> Well... the situation with LP is not so sim
ovyov
***
--- On Thu, 7/23/09, Peter Y. Zavalij wrote:
From: Peter Y. Zavalij
Subject: RE: LP factor in the Rietveld refinement
To: rietveld_l@ill.fr
Date: Thursday, July 23, 2009, 4:52 AM
Well... the situation with LP is not so simple. Using TOPA
Lab: (301)405-3230
Fax: (301)314-9121
-Original Message-
From: Ross Williams [mailto:ross.willi...@curtin.edu.au]
Sent: Wednesday, July 22, 2009 8:43 PM
To: Jon Wright; xiu...@ualberta.ca
Cc: rietveld_l@ill.fr
Subject: RE: LP factor in the Rietveld refinement
Hi Xiujun,
Jon is correct, but
factor in the Rietveld refinement
Sounds like the parameter is the monochromator angle you would need to
use to convert an unpolarised beam into a beam with the polarisation
state you have (eg, 90 degrees gives 100% polarised). Don't confuse this
with the actual monochromator angle at the synchr
Sounds like the parameter is the monochromator angle you would need to
use to convert an unpolarised beam into a beam with the polarisation
state you have (eg, 90 degrees gives 100% polarised). Don't confuse this
with the actual monochromator angle at the synchrotron, as the bean is
usually pol
Hello, everyone,
I have some questions about the refinement in Topas.
When we put the instrument parameters, we always include the LP
factor, and set it to a constant value. I thought LP factor is a
function of theta and not a constant value, so my question is what
exact the constant value
xp5
- Original Message -
From: "Mingtao Li" <[EMAIL PROTECTED]>
To:
Sent: Sunday, November 30, 2008 1:11 AM
Subject: I am a newcome, how can I begin my rietveld refinement analysis
Hi, everyone,
I am a newcome to Rietveld refinement. Actually I am a student
majore
11/30/2008 +0800, Mingtao Li wrote:
>Hi, everyone,
> I am a newcome to Rietveld refinement. Actually I am a student
>majored in photocatalytic splitting water for hydrogen production. We
>want to analysis the structures of our photocatalysts via rietveld
>method. For that purpose
, K. Marx 42, Krasnoyarsk, Russia
www.icct.ru/eng/content/persons/Sol_LA
www.geocities.com/l_solovyov
*
--- On Sun, 11/30/08, Mingtao Li <[EMAIL PROTECTED]> wrote:
Hi, everyone,
I am a newcome to Rietveld refinement. Actually
Hi, everyone,
I am a newcome to Rietveld refinement. Actually I am a student
majored in photocatalytic splitting water for hydrogen production. We
want to analysis the structures of our photocatalysts via rietveld
method. For that purpose we got a X'pert Pro diffractionmeter from
Panal
Hi, everyone,
I am a newcome to Rietveld refinement. Actually I am a student
majored in photocatalytic splitting water for hydrogen production. We
want to analysis the structures of our photocatalysts via rietveld
method. For that purpose we got a X'pert Pro diffractionmeter from
Panal
On Mar 14, 2008, at 5:41 AM, Franz Werner wrote:
w=1/Yo**2 [weighting] is proposed ("By using the new weighting
scheme, the accuracy of positional parameters of the test sample
was significantly improved relative to the weight function 1/Yo,
which weights the medium and strong intensities m
Dear Rietvelders
I just stumbled on the paper "Weighting Scheme for the Minimization Function in
Rietveld Refinement" (H. Toraya, http://dx.doi.org/10.1107/S0021889897011096)
where w=1/Yo**2 is proposed ("By using the new weighting scheme, the accuracy
of positional paramet
Dear All,
On behalf of the Physical Crystallography Group of the British
Crystallographic Association, I am pleased to announce the Powder
Diffraction and Rietveld Refinement School at Durham University, 30th
March-3rd April 2008. Lectures will be given by Jeremy Cockcroft, Andy
Fitch, John
Forwarded from Mike Glazer:
I think that very often people tend to overlook what is in fact the
primary purpose of Rietveld: it is to get structural parameters out that
have some meaning. The Rietveld method consists of two sets of
refinement variables. First of all you have the structural paramet
bject: Re: Problems using TOPAS R (Rietveld refinement)
My limited experience with X-ray capillary measurements of ultra fine clay
minerals suggests that you could have significant preferred orientation along
the b* axis. It is actually a good way of determining aspect ratios in
phyllosili
From: Whitfield, Pamela [mailto:[EMAIL PROTECTED]
Sent: Wednesday, March 21, 2007 7:51 AM
To: rietveld_l@ill.fr
Subject: RE: Re: Problems using TOPAS R (Rietveld refinement)
I have to disagree with that; at least on a practical front with lab XRD. I
have done measurements myself with samples
investigate it.
Cheers
Alan
-Original Message-
From: Lubomir Smrcok [mailto:[EMAIL PROTECTED]
Sent: Wednesday, 21 March 2007 5:50 PM
To: rietveld_l@ill.fr
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Gentlemen,
I've been listening for a week or so and I am really wond
e off
for wollastonite though!
I will shut up at this point as I trying to avoid doing clay analysis!
Pam
-Original Message-
From: David L. Bish [mailto:[EMAIL PROTECTED]
Sent: March 21, 2007 9:11 AM
To: rietveld_l@ill.fr
Subject: Re: Problems using TOPAS R
One often hears of attempts to "eliminate" preferred orientation in
diffraction patterns of layer silicates using transmission
measurements. Keep in mind that if PO is a problem in reflection geometry,
it will also affect transmission measurements, in a manner potentially
similar to flat-plate
leeberg [mailto:[EMAIL PROTECTED]
Sent: Wednesday, 21 March 2007 7:48 PM
To: rietveld_l@ill.fr
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Dear colleagues,
sorry, my mail should go directly to Leandro, but I used this damned reply
buttom...
My answer was related to Leandro's quest
Dear colleagues,
sorry, my mail should go directly to Leandro, but I used this damned
reply buttom...
My answer was related to Leandro's questions regarding these line
broadening models. I realised that Leandro is going on to apply a
Rietveld program for phase quantification, including kaolinit
Dear Lubomir Smrock,
linear pattern analysis is _not_ Rietveld, this was a common QPA
method prior to Rietveld QPA. In a Rietvel QPA, one must refine
the lattice parameter at least. And that makes it nonlinear.
Depending on the sample, one may decide to add more nonlinear
details to the refinemen
Gentlemen,
I've been listening for a week or so and I am really wondering what do you
want to get ... Actually you are setting up a "refinement", whose results
will be, at least, inaccurate. I am always surprised by attempts to refine
crystal structure of a disordered sheet silicate from powders, e
Dear Leandro Bravo,
some comments below:
Leandro Bravo schrieb:
In the refinement of chlorite minerals with well defined disordering
(layers shifting by exactly b/3 along the three pseudohexagonal Y
axis), you separate the peaks into k = 3.n (relative sharp, less
intensive peak) and k 3.n
Regards,
Leandro
From: "AlanCoelho"
<[EMAIL PROTECTED]>
Reply-To: rietveld_l@ill.fr
To:
Subject: RE: Problems using TOPAS R (Rietveld refinement)
Date: Fri, 16 Mar 2007 09:56:33 +1100
Leandro
Not sure what the purpose of your refinement is but if it's
quantification
then your
Mr. Kleeberg,
Read the paper that you send to me, ´´RIETVELD ANALYSIS OF DISORDERED LAYER
SILICATES``, and I have some questions about it.
In the refinement of chlorite minerals with well defined disordering (layers
shifting by exactly b/3 along the three pseudohexagonal Y axis), you
separat
= Exp(-b />D_spacing^2)
Does it give reasonable values!?
Regards,
Leandro
From: "AlanCoelho" <[EMAIL PROTECTED]>
Reply-To: rietveld_l@ill.fr
To:
Subject: RE: Problems using TOPAS R (Rietveld refinement)
Date: Fri, 16 Mar 2007 09:56:33 +1100
Leandro
Not sure what the purpose
(FP) for peak shape, the values I put in
the instrument description play a major role in FP, am I right?
No. The misfit in your Rietveld refinement of kaolinite you get by using
published atomic coordinates and temperature factors does definitely not
arise from wrong published structure date
I know that refining the atoms positions is ´´too much´´, exagerated. But is
the only way I can make the calculated DRX pattern fit with the measured
one. There must a problem in the instrument details since I´m using
Fundamental Parameters (FP) for peak shape, the values I put in the
instrumen
AM
To: rietveld_l@ill.fr
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Ok, I´m starting to have sucess in the kaolinite refinement, the
quantification is giving me reasonable values. I´m refining the thermal
factors, all the atoms positions in the kaolinite, the lattice parameters
an
PM
To: rietveld_l@ill.fr
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Ok, I´m starting to have sucess in the kaolinite refinement, the
quantification is giving me reasonable values. I´m refining the thermal
factors, all the atoms positions in the kaolinite, the lattice parameters
Ok, I´m starting to have sucess in the kaolinite refinement, the
quantification is giving me reasonable values. I´m refining the thermal
factors, all the atoms positions in the kaolinite, the lattice parameters
and the cystallite size. Lattice parameters and crystallite size are giving
me very
Thanks Alan,
our first trial was:
Bergmann, J., Kleeberg, R. (1998) Rietveld analysis of disordered layer
silicates. Mat. Sci. Forum, 278-281 (1): 300-305.
Application to kaolinite at:
http://www.bgmn.de/kaolin.html
and for more disordered stuff:
http://www.bgmn.de/smectite.html
Far from beeing
Or, to see how bad the results from Rietveld refinements of kaolintes are
try review
paper in
Zeitschrift fuer Kristallographie 210(3) 177-183, 1997
lubo smrcok
On Wed, 14 Mar 2007, Alan Hewat wrote:
> Reinhard Kleeberg said:
> > There are not so much trials published to find a
> > working solu
Reinhard Kleeberg said:
> There are not so much trials published to find a
> working solution for practical Rietveld quantification of clays. One
> would be a self-citation of a paper, so I can't do this here in the list.
A good one is :-)
Pitfalls in Rietveld Phase Quantification of Complex Samp
treatment
Drits, V.A. and Tchoubar, C. X-ray diffraction by disordered lamellar
structures. Springer, 1990 ISBN 3-540-51222-5
Thus, Rietveld refinement of such structures needs for a model what can
treat the "anisotropic line broadening" and all the other diffraction
effects caused by
analysis using time-of-flight neutron
powder diffraction data (1997) Clays and Clay Minerals 45, 781-788
Bish, D.L. Rietveld refinement of the kaolinite structure at 1.5K (1993)
Clays and Clay Minerals 41, 738-744
Bish, D.L.;von Dreele, R.B. Rietveld refinement of non-hydrogen atomic
positions i
ietveld_l@ill.fr
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Date: Mon, 12 Mar 2007 13:35:54 -0300
I think that I just did a good job in my quantification: 50,2% calcite and
49,8% dolomite. Now I´m moving foward to a sinthetic mixture of calcite,
dolomite and kaolinite.
I have other
@ill.fr"
Subject: Re: Problems using TOPAS R (Rietveld refinement)
Date: Mon, 12 Mar 2007 10:39:41 -0600
Leandro :
here is an example of calcite I used. You can use min and max to confine
the parameters.
One way to know whether it is right is to mix a known fraction of a
compound, e.g. Zn
Leandro :
here is an example of calcite I used. You can use min and max to confine the
parameters.
One way to know whether it is right is to mix a known fraction of a compound,
e.g. ZnO with a ratio of original sample/ZnO=100/15.
At the end of the refinement, you have N components with N corr
Hi, guys,
I´m having some trouble using the Bruker software TOPAS R, right now I´m
quantifying a sinthetic sample with 50% of calcite and 50% of dolomite.
Check the following questions an help me if you can.
1) I´m using the CIF files from ICSD, but when I put it in the software it
gives me
Dear
Colleague,The PCG/SCMP (Physical Crystallography Group of the
BritishCrystallographic Association/Structural Condensed Matter Physics
groupof the Institute of Physics) will be holding a 3 day Rietveld
refinementtraining course at the University of Durham , 7-10th of January
2007..The c
Dear All,
I am mainly dealing with metallic alloys. In most of the cases the alloying
element is very less (2%-5%, weight) and are not detected by XRD.
In this situation how to do Reitveld refinement of the XRD pattern from these
alloys.
If I perform Rieteveld refinement only giving the informa
Directly the distributions (both) using Fourier Transform (an FFT).
Sufficiently fast, implementing it the correct way.
Luca
On Nov 24, 2004, at 12:14, Leonid Solovyov wrote:
actually I implemented the size and strain distributions (both) in my
Rietveld code (Maud) and I demoed it
>actually I implemented the size and strain distributions (both) in my
>Rietveld code (Maud) and I demoed it in Praha beginning of September
Good news! I look forward to see the program. Which profile function do
you use for size distribution analysis? Hopefully not TCH
pseudo-Voigt...
Regards,
> actually I implemented the size and strain distributions (both) in my
> Rietveld code (Maud) and I demoed it in Praha beginning of September.
Thanks Luca,
I'm very, very happy to hear that. Really you are moving very fast!
I was prepared to come in Prague but, unfortunately, I had to cancel on
True Nick,
actually I implemented the size and strain distributions (both) in my
Rietveld code (Maud) and I demoed it in Praha beginning of September.
Actually the program was not released and it is still under testing
because I changed also the interface and other parts that needed more
work;
> gamma, or whatever we assume it to be. On the former, it is easy to see if
> observed profiles can't be successfully fit ("super-Lorentzian" peak
shapes,
> for instance), which means that the TCH peak shape cannot be used.
However,
> an assumption that physically broadened profiles (size and str
Thank you, Davor!
Despite several HOWEVERs in your message it clarifies the situation.
Best wishes,
Leonid
__
Do you Yahoo!?
Meet the all-new My Yahoo! - Try it today!
http://my.yahoo.com
Yes, one can determine size distribution parameters by using Rietveld
refinement. In particular, the lognormal size distribution is defined by two
parameters (say, the average radius and the distribution dispersion, see,
for instance, (2) and (3) of JAC 37 (2004) 911, SSRR for short here, or
other
he problem, the initial question,
> which, actually, concerned the size distribution from Rietveld
> refinement, seems to be unsettled.
> Can we derive ANY information on the crystallite size distribution
> (based on sensible assumptions) from the Thompson-Cox-Hastings
> size-broadeni
train Round
Robin profiles. Where do we loose information applying THC in Rietveld
refinement? In this "ALMOST"?
Or, maybe, the distribution dispersion was erroneously determined in
the SSRR and, actually, this information can not be unambiguously
derived solel
o a search match, a structure solution or,
even worse, a Rietveld refinement on a material for which we don't know
any chemical information...
Going back to Leonid's question, well the answer is easy: check the
premises... the assumptions behind the use of the TCH function are not
compati
Dear Rietvelders,
Despite the heated discussion of the problem, the initial question,
which, actually, concerned the size distribution from Rietveld
refinement, seems to be unsettled.
Can we derive ANY information on the crystallite size distribution
(based on sensible assumptions) from the
strain/size anisotropy in the Rietveld method, I have myself a
> contribution:"The (hkl) dependence of diffraction-line broadening
> caused by strain and
> size for all Laue groups in Rietveld refinement, N. C. Popa, J.
> Appl. Cryst.
> (1998) 31, 176-180."
> Could
2000) 33, 964-974 and Popa &
Balzar JAC (2002) 35, 338-346.
Concerning previous (phenomenological) works trying to take account of
strain/size anisotropy in the Rietveld method, I have myself a contribution:
"The (hkl) dependence of diffraction-line broadening caused by strain and
size for
aused by strain and
size for all Laue groups in Rietveld refinement, N. C. Popa, J. Appl. Cryst.
(1998) 31, 176-180."
Could I be so stupid to say that such kind of works, including mine, are
nothing?
Best wishes,
Nicolae Popa
Hi,
With regards to size/shape/distribution analysis of line profiles, the papers
by Armstrong et al. (2004a,b,c) discusses a Bayesian/Maximum Entropy method,
that determines these quantities from the line profile data. This can also
resolve bimodal distributions from line profile data.
This
Title: RE: rietveld refinement
I'm afraid that you got the wrong end of the stick -I wasn't talking about the application of peak broadening to size distribution, I was commenting that determining crystallite shape is perfectly possible (some comments were flying that said other
It is also true that no development has been done for anisotropy. Not yet!
Well, if all previous works about trying to take account of size/strain
anisotropy in the Rietveld method are nothing yet, this allows to
close the discussion. Let us wait for really serious developments to
come.
Armel
Title: RE: rietveld refinement
Doesn't help with a size
distribution, as it only works well for a relatively monodisperse material -
but it does work under some circumstances.
Pam
I disagree, it works also
for large dispersion. One example you can find in JAC (200
> So I cannot let say that "Significantly different "physical"
> size distributions could describe equally well the peak profile".
> This is confusing. You may say that : significantly different
> crystallite shapes could describe equally well the peak profile
> in cubic symmetry. I am not sure th
can anyone send me a soft copy of the following paper
J. Appl. Cryst. (1978). 11, 50-55.
thanks
venkat
+++
M Venkata Kamalakar
Junior Research Fellow,
S.N.Bose.National Centre for Basic Sciences,
Block-JD, Sector-3, Salt Lake,
Kolkata, Pin: 7
can you please send me the soft copy of the paper you referred to. We don't
have access to that journal...
very much sincerely yours
venkat
From: Armel Le Bail <[EMAIL PROTECTED]>
To: [EMAIL PROTECTED]
Sent: Fri, 19 N
Let me put a more particular question on the size estimation from
Rietveld refinement.
If we refined the size-broadening parameters P and X of the
Thompson-Cox-Hastings function (as they are defined in J. Appl. Cryst.
(2004) 911) and corrected them for the instrumental contribution, then
can we
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