Hi Armel,
A more extreme example was in Acta D56, 1549-1533 (2000) where a protein
structure (a new insulin phase) was solved by rigid body Rietveld refinement
from a synchrotron powder data set & subsequently confirmed by a single crystal
analysis (see Acta Cryst. (2001). D57, 1091-1100). NB:
John ( others),
The best way to determine %crystallinity (or %amorphous) is to do spiking
experiments with material with known (preferably ~100%) crystallinity. The
change in the apparent phase fractions by Bragg intensities as compared to that
expected from the masses can be used to estimate
: Von Dreele, Robert B. [mailto:[EMAIL PROTECTED]
Sent: Friday, February 15, 2008 6:37 AM
To: rietveld_l@ill.fr
Subject: RE: advice on new powder diffractometer
Hi Kurt,
If you plot the results in POWPLOT do the statistical analysis what
does the delt/sig vs 2-theta plot look like? If weights
Hi Kurt,
If you plot the results in POWPLOT do the statistical analysis what does
the delt/sig vs 2-theta plot look like? If weights are right then the band of
delt/sig ought to be roughly 2-3 sig wide. Is your data in cpm? Some
instruments make that by default. That will mess up the
Hi,
Not sure - need to know the context. It may be a mistyped Shoenflies
symbol for either space group P 21 21 2 (orthorhombic) or P321
(trigonal).
Bob Von Dreele
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
Hi,
Some of the Shkl values for the Stephens' anisotropic broadening can be
negative. However, negative S400, S040 S004 terms have no physical meaning;
best is to probably set them to zero not refine them further. GSAS has a
plotting routine (coupled to gnuplot) that displays the microstrain
Hi All,
From the IPNS web page:
Message From the Director
Dear Colleagues
It's my sad duty to inform you of some unfortunate news regarding the
future of IPNS. As you may know, the omnibus bill that was signed into
law by President Bush just before the end of the year provided funding
for our
Dear Ramadas,
Your problem is that your Si atoms are related by equivalent positions
to the ones you need for your restraint. You need to get all of them
within bonding distance of each other by transforming them via the
symmetry operators. Then angle restraints will be easy. Run disagl to
get
Dear Ramadas,
Sometimes getting a Rietveld refinement to start is hard. You might try
guessing at what you think the scale ought to be (relative peak
heights would do) and set it to that value and not refine it (i.e. turn
off the refine flag). Then you might see what is really wrong (misset
Dear Irvin,
You seem to be wanting to put in a special form factor for your D2
molecule. In GSAS special form factors need special element names -
these are QA, QB, ... Then use this name for the atom type for
your D2 put in just one of these. If it failed let me have a look at
your .EXP file.
yes?
From: Davide Levy [mailto:[EMAIL PROTECTED]
Sent: Tue 11/27/2007 7:48 AM
To: rietveld_l@ill.fr
Subject: GSAS on Windows Vista
hi,
I am changing PC and I would like to know if there are problem to run
GSAS-EXPGUI with Windows Vista.
thank you
Davide
Hi All,
I have placed new Windows, MacOSX (for Intel) Fedora 5 versions of
GSAS on the ccp14 web site. changes are:
Nov. 12, 2007
1. Oops, forgot some arrays - GSAS now WILL do up to 200,000 profile
points in a single powder pattern.
2. A new weight modification for powder data is available. In
Hi All,
I have placed on the ccp14 ftp server new versions of GSAS for Windows,
RedHat Enterprise 4, Fedora 5 and Mac OSX 4. The changes are:
1. The maximum number of profile points in an individual powder pattern
is now 200,000.
2. The program OVERLP has been extensively modified. The
divide by 8*pi^2 (~80), that gets U (mean sq atom displacement)
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Duncan, Jo [mailto:[EMAIL PROTECTED]
Sent: Thursday, September 06, 2007 10:46 AM
Lachland,
Ever been to a Pittsburgh Diffraction Conference? I wonder if you could do a
talk on this charge flipping stuff in a session I'm organizing. Meeting is Oct
26-28 in Buffalo. Please let me know ASAP.
Bob
From: Lachlan Cranswick [mailto:[EMAIL
Hi All,
After some thrashing around and getting used to the unique Apple
approach to computers, I now have made a MacOSX version of GSAS. This
supercedes the one prepared by Brian Toby and is identical to the
Windows/Linux versions released about a month ago (June 12). It was
compiled with g77 and
Dear Stefan ( all, I suppose),
From the original formulation by Caglioti, et al. U0, V0 W0 for a
nonfocusing neutron CW instrument and describes a parabolic curve with
the minimum at roughly the 2-theta angle that matches the monochromator
take-off (really 2-theta) angle. For a Bragg-Brentano
Hi Everyone,
New Windows and Linux versions of GSAS have been downloaded to the CCP14
web site. The changes (since 2/2007) are:
June 12, 2007
1. A new record in the .EXP file has been defined:
'HSTnn NFOBS' the number of observed reflections for each phase in a
histogram.
2. REFLIST now can
huge
values are obtained for Patterson plot. Is there a way to normalized the
values, for example, to number of electrons/A^3? Many thanks.
Sincerely,
Ling Yang
-Original Message-
From: Von Dreele, Robert B. [mailto:[EMAIL PROTECTED]
Sent: Thursday, May 03, 2007 5:26 PM
To: rietveld_l
Hi All,
New versions of GSAS for Windows and Fedora-5 have been placed on the CCP14 web
server. The changes are as follows:
May 2, 2007
1. A new record in the .EXP file has been defined:
'HSTnn NFOBS' the number of observed reflections for each phase in a histogram.
2. REFLIST now can prepare a
Hi,
A few important points:
1) Removing Ka2 from the powder pattern is not necessary for running GSAS (or
Fullpoof for that matter). Both represent the Ka1-Ka2 doublet quite nicely.
More important, most Ka2 stripping routines can adversly distort the data
messing up the result from a Rietveld
Juske,
One point you should know the background in a TOF powder diffraction
pattern is not high - that is a nearly constant background multiplied by
a strongly varying incident spectrum which is much higher at short TOF
than at long TOF. Do a divide by incident spectrum and you wll see
what I
Hi,
I have just down loaded 3 new versions of GSAS to the ccp14 web site.
These are for MS Windows, RedHat Enterprise 4 linux Fedora 4 linux.
The last two are not interchangable as the former has more of the
libraries within the distribution. The changes are a) a bug fix for
gsas2cif and b)
I should add about cif is that there exists a number fundamental
incompatibilities between pdCIF mmCIF. One main issue, as I understand
it, is that pdCIF naturally can describe multiple data sets (powder
patterns) used in a single structure analysis - mmCIF seems to forbid
this. This will cause
However, the profile shape functions are not simple functions of Q but are
simple (Gaussian Lorentzian) functions of 2-theta. Case closed.
From: Klaus-Dieter Liss [mailto:[EMAIL PROTECTED]
Sent: Wed 2/21/2007 4:03 AM
To: rietveld_l@ill.fr
Subject: Powder
OK, I did play about display some Q-space (Q=2pi/d) plots in GSAS. It
will be an option in the next release. Pretty similar to conventional
2-theta plots - just a slight squishing of the scale at the upper end.
Might not be really desirable for complex patterns. Some TOF data where
data was
Hi All,
A couple of points about lattice parameter constraints:
1) Beware of using damping; it isn't needed especially for lattice parameters
in Rietveld refinements and it will mess up the intent of constraints if not
very carefully used.
2) The constraints are on the reciprocal metric tensor
Dear All ( Franz),
Use FXYE format. The positions given actually override those that would be
calculated from the average stepwidth given on the BANK record where it
matters. This scheme is only valid where the goniometer doesn't give truly
uniform steps but jitters about some average. Most
Dear Franz,
I'm sure there will be many opinions on this but here goes from me.
The sig on the lattice parameters is only a measure of precision for the
value and is not directly related to the microstrain broadening. It is more a
measure of how well the peak positions can be collectively
Dear Friedrich,
There are inequivalent reflections that overlap even in cubic
structures; those where h^2+k^2+l^2 are the same will have identical
d-spacings (e.g. 300 221, 410 322). Check through the list of
reflections to see those that have identical d-spacings; these are also
listed in the
Dear Apu,
Compilations of scattering factors in International Tables for X-ray
Crystallography go to sin(theta)/lambda = 2. Use those.
Bob Von Dreele
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: [EMAIL PROTECTED]
Dear Milinda,
In the menu for introducing the diffuse scattering function setting initial
values (especially for R - interatomic distance), set the refinement flags
with V (as usual). If it didn't refine then your starting valued are not
good. Set A=1.0, R to an interatomic distance U=0.005
Sajeev,
There is a lot of information like this in the GSAS Manual.
Bob Von Dreele
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]
Sent: Thursday, June 29, 2006 11:31 AM
To:
Could probably do much the same thing in EXCEL or some other spreadsheet
program, I suppose
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Jon Wright [mailto:[EMAIL PROTECTED]
Sent: Wednesday, May 31, 2006 8:54 AM
To:
Hi,
Whoever is running the CCP14 site needs to capture these FAQ type
messages stick them into the appropriate spot in the web site for
others to find later. This question ( ones like it) does come up
occasionally.
Bob Von Dreele
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne,
to contact the CCP14 or me!
http://www.ccp14.ac.uk/people/people.htm
Thanks
Richard
Von Dreele, Robert B. wrote:
Hi,
Whoever is running the CCP14 site needs to capture these FAQ type
messages stick them into the appropriate spot in the web site for
others to find later. This question
available via www.ccp14.ac.ukat
http://www.ccp14.ac.uk/solution/rietveldfaq.html
I hope this helps, suggestions or requests for the CCP14 site are
always welcomed and greatly received!
Richard
Von Dreele, Robert B. wrote:
Hi,
Whoever is running the CCP14 site needs to capture these FAQ
John,
As was said by Francesco, you really must go back to the instrument
responsible for the diffractometer you used to collect the data for that
instrument parameter file. An old example of such a file is
\gsas\example\inst_tof.prm (the instrument doesn't exist any longer),
however iparm files
Title: Message
Hi,
A new Windows
version of GSAS has been placed on the CCP14 web site. There are some changes
since the Apr. 7, 2005 release. These are:
June 8, 20051.
Modified GENLES so that the Marquardt matrix modifier is changed before the
current cycle. It will decrease by 20% or less
Title: Message
Don,
As
Allen Larson noted GSAS only uses the 2nd setting for space groups that have two
(e.g. F d 3 m) so that he inversion center is placed at the origin. The eta
alumina structure you have is for the 1st setting. To convert from 1st to 2nd
subtract 1/8,1/8,1/8 from all
Title: Message
Gerard,
In
GSAS there is a GENLES "print" option that will give the covariance terms larger
than +/- 0.5 in the list file. There aren't as many large ones as you might
think apart from the various background terms.
Bob
Von Dreele
R.B. Von Dreele
IPNS Division
Argonne
Nic,
Thanks,it will take a while (as usual) to implement.
Bob
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Nicolae Popa [mailto:[EMAIL PROTECTED]
Sent: Sunday, April 17, 2005 1:27 AM
To: rietveld_l@ill.fr
Bob,
A nice
Nic,
Well, I have been tempted from time to time to implement a log normal type
distribution in on eof the profile functions. A nice math description
ameanable to RR would help.
Bob
From: Nicolae Popa [mailto:[EMAIL PROTECTED]
Sent: Fri 4/15/2005 2:30 AM
To:
Alan,
Ah - the rocks dust model. It works well.
Bob
From: alan coelho [mailto:[EMAIL PROTECTED]
Sent: Fri 4/15/2005 5:30 AM
To: rietveld_l@ill.fr
Nicolae, Nick, Bob, Leonid,
I have looked at many patterns (recorded by others) and a few cases have shown
Title: Message
A word
from a "provider" of a Rietveld code (please don't call me a "programmer").
"But if c0.4 any
pV fails" - OK, for what fraction of the universe of "real world" samples is
"c"0.4? I suspect, given the general success of the TCH pseudoVoigt
function, that it is
Title: Message
Nic,
I know
about "super Lorentzians". Trouble is that many of those older reports were from
Rietveld refinements "pre TCH" and used a formulation of the pseudo-Voigt which
forced the FWHM of the Gaussian and Lorentzian components to be equal and
allowed the mixing
Title: Message
Nic,
This
is true for the internal math but the TCH function was assembled to reproduce
the true Voigt over the entire range of differing Lorentz and Gauss FWHM values
so it works as if the two FWHM components are independent. As for your question,
I'm not aware that anyone
Guys,
This appeared in a Rietveld e-mail a bit ago needs a comment:
While I can understand the general rationale for the idea (minimize the
weight of the very strong reflections to the final integrated intensity
for the reflection)
The fact of the matter is that most least squares programs
Title: Message
Hi
Folks,
A new version of the
Windows GSAS has been placed on the CCP14 web site. The changes from the Jan.
27, 2005 version are relatively modest. These are:
Mar. 22, 20051.
Corrected some of the parameter names for the P. Stephens peak shape parameters.
These were mostly
Dear Yaroslav (and others),
Use cylindrical symmetry for flat plate Bragg-Brentano samples. There
isn't sufficient information in a single scan to do more than that.
Conseqently wnen you used mmm ample symmetry you got nonsense
(J=400!!). Use POLFPLOT option A to plot the resulting axial
Jools,
GSAS gives R(F^2)in the .LST file for each powder histogram assuming the
Fo extraction flag is on (default). Generally R(F) = 0.5* R(F^2).
Bob Von Dreele
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Jools
Folks,
FYI.
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Peter L. Lee [mailto:[EMAIL PROTECTED]
Sent: Friday, January 21, 2005 11:32 AM
To: Mitchell, John; Jorgensen, James D.; Mark A Beno; Von Dreele, Robert
B.; Quintana
Larry,
Out of curiousity I downloaded a copy of DrawXTL (Windows version source as
well). BTW still more work on the FCJ function. It had a bad habit of
misbehaving for reflections at exactly 90. deg 2-theta tmp=0.0. It seems
that the choice of F=0.0 was a bad one (divide by zero crashes,
interesting, one should try one's own name!
From: Armel Le Bail [mailto:[EMAIL PROTECTED]
Sent: Thu 25/11/2004 04:12
To: [EMAIL PROTECTED]
Cc: [EMAIL PROTECTED]
Hi,
It seems that Google Scholar is a big support to
a more open access to the Knowledge.
There
Dear Ling Fei ( others),
GSAS requires all powder data to be records 80 visible characters long and each
terminated with an additional 2 characters (CR LF). Thus, the length of the
file in bytes should be divisible by 82. CNVFILE will try to fix this; it does
not do any other formatting.
Hi,
I'll be placing a new Windows version of GSAS onto the CCP14 web site
immediately. The fixes are noted below. As usual thanks to all, especially
those who find bugs errors.
Bob Von Dreele
Nov. 13, 2004
1. Fixed problem in CW function nos. 3-5 (Finger, Cox Jephcoat function)
where an odd
please remove your autoreply. It is not useful.
From: [EMAIL PROTECTED] on behalf of [EMAIL PROTECTED]
Sent: Sat 11/13/2004 2:37 PM
To: Von Dreele, Robert B.
[EMAIL PROTECTED]
Dear Donita,
I'm sure you know that the vanadyl (V=0) bond length is short - you could put in a
restraint on its length as one possible control on your refinement. If their sites are
partially occupied then make sure you have a constraint to make FRAC(V)=FRAC(O). I
don't particularly understand
Try the GSAS Manual - a lot is in there.
Bob Von Dreele
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Thu 11/4/2004 10:19 AM
To: [EMAIL PROTECTED]
Hello !
I need papers about the mathematical aspects of Rietveld refinement.
In my countyr (Colombia)
Pam,
I hope that when you used GSAS you entered (as per instructions) p 31 1
2 and not p3112.
Bob
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-
From: Whitfield, Pamela [mailto:[EMAIL PROTECTED]
Sent: Monday, October 18, 2004 12:50
Alan,
One of your operators is a typo.
-x+y, y, -z+1/3 should be Y-X Y 1/3-Z
Bob
From: alan coelho [mailto:[EMAIL PROTECTED]
Sent: Mon 10/18/2004 3:16 PM
To: [EMAIL PROTECTED]
Pam,
As a developer and someone who uses other software to test
Marcelo,
Run REFLIST request the file output of one phase of reflections to an ASCII file.
FWHM is the 7th column.
Bob Von Dreele
From: Marcelo J.G. Silva [mailto:[EMAIL PROTECTED]
Sent: Fri 8/27/2004 2:23 PM
To: Rietveld List
Dear all,
Even though I know
Jon others,
Well, there is an attempt at this in GSAS - the diffuse scattering functions for
fitting these contributions separate from the background functions. These things
have three forms related to the Debye equations formulated for glasses. The possibly
neat thing about them is that they
I'd only add that given the clue that the peak in GaInAs is split from the PDF then
one should model it that way in a Rietveld refinement. It should agree. The thrown
away info in a Rietveld refinement is also evident in the Bragg peak intensities -
shows up as funny thermal parameters, low
Dear Darin others,
The trick here is to realize the effect of the different site multiplicities.
Moreover, remember that the constraint applies to the shifts not the values. So
start the site fractions with the right stereochemistry - you can put all Co in one
site all Fe in the other with
Dear Christoph (and others),
The constraints within GSAS are limited to pairs of parameters. You describe a
circumstance in which the total unit cell contents from a multiple atom sites is known
from stoichiometry; this is best handled with a restraint. The restraints in GSAS
are not accessible
Hi All,
There is a new version of Windows GSAS on the CCP14 web server. The biggest change is
that it will now do Pawley style extractions for one set of reflections from multiple
powder patterns. This is done inside GENLES. See below for note on this other
changes. Linux other versions will
Dear Marcelo ( others),
GSAS should do texture (sph. harmonics) with film data (or image plate) powder data.
Image needs to be divided up in to 'pie' sections integrated to give a sequence of
patterns about the azimuth. The read them as separate histograms in GSAS give each
the appropriate
Jon,
I risk a public reply here. One possibility everyone should be open to is that a real
phase change has occured during some experimental manipulation of your sample. Some
phase changes are quite subtle and involve only slight (and at first sight) quite odd
line broadening. Higher resolution
Apu,
1. For now use the inst_xry.prm file in \gsas\examples.
2. POLA is appropriate only for X-ray data not neutron data. GSAS knows the
difference.
Bob Von Dreele
From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED]
Sent: Mon 4/26/2004 11:45 AM
To: [EMAIL
Dear Marit ( others),
The current limit is 9 points - that's not your problem.
Bob Von Dreele
-Original Message-
From: Marit Stange [mailto:[EMAIL PROTECTED]
Sent: Thu 4/22/2004 9:36 AM
To: [EMAIL PROTECTED]
Hi,
I have a problem with a data file (SR-XRD data, 19400 points, 2theta;
Title: Message
Hi
Folks,
There is now a new
Linux version of GSAS that matches the recent Windows version. Lots of changes
since the last Linux one. See GSASNEWS.TXT for details.
Find it at ftp://ftp.ccp14.ac.uk/ccp14/ftp-mirror/gsas/public/gsas/in
the linux subdirectory.
As usual let me
To: [EMAIL PROTECTED]
Hello Bob Von Dreele and all,
I am Marcelo Gomes da Silva, PhD Student at PennState.
About this new version, is it avaliable for downlaod already?
If so, where?
Appreciate everybody's attention.
Marcelo
- Original Message -
From: Von Dreele, Robert B. [EMAIL
Hi all,
There is a new version of GSAS for Windows; Linux to follow soon. The changes are:
GSAS News...
April 15, 2004 (tax day in USA)
1. A small cosmetic fix to the g-value editing routine.
2. There is now an option in histogram editing to set aside a certain fraction of the
profile
Stephen,
Whether the space group is centrosymmetric or not isn't the issue. The question is
whether it is polar or not. P2/n is not polar (i.e. origin defined relative to some
symmetry element) but P2 is polar (i.e y coordinate not chosen relative to a symmetry
element).
Bob Von Dreele
:44, Von Dreele, Robert B. wrote:
Dear Arie,
Some of this has been discussed earlier but in a LeBail refinement in GSAS the Ka1
and Ka2 reflections are treated as independent and the 2:1 intensity ratio is not
used. This arises because of the severe computational difficulty of connecting
Dear Stephen ( others),
I know there have been a number of replies to this since P2/n does have an inversion
center which is positioned at the unit cell origin. However, if the space group is Pn
(or P2) then the location of the origin is arbitrary on one or more axes. GSAS does
automatically
Dear Arie,
Some of this has been discussed earlier but in a LeBail refinement in GSAS the Ka1 and
Ka2 reflections are treated as independent and the 2:1 intensity ratio is not used.
This arises because of the severe computational difficulty of connecting the
intensities of these paired
Hi,
According to GSASNEWS.TXT from July 6,1999.
19. RAWPLOT now has the option for fitting positions, areas shapes of up
to 30 individual reflections in a powder pattern using the same profile functions
available in GENLES.
GSASNEWS.TXT is part of the standard GSAS distribution and is in the
Hi,
There is a new version of GSAS for Windows. The Linux one will be out in a bit. Below
are lines from GSASNEWS.TXT with details of the new things fixes in this version. In
brief, there is now conjugate gradient refinement, new tables of f' f for 10
standard wavelengths (CoKa fans can now
Donna (and anyone else who wonders about this),
In gsas\examples there is an iparm file (inst_xry.prm) that can be used for most any
Bragg-Brentano powder diffractometer. These instruments all perform more or less
equally independent of manufacturer with respect to the things of interest for
Henry,
Do you have the correct polarization correction (POLA=0.95, IPOL=0) fro synchrotron
radiation? Did you just use the defaults for Uiso (=0.025)? If so that is too high for
something like HfO2 for which UISO might be closer to 0.004. Either of these would do
what you observe.
Bob Von
Liliana,
GSAS will refine the value of the absorption coefficient for neutron TOF data quite
easily (I recall one message of yours mentioned that your data was of this flavor).
Just turn on the flag. Your Uiso's should rise for all atoms making those for the
heavy atoms positive. The ABS value
crystal analysis, is there an
accepted limit for R(F2) or any other parameter like
Rexp to follow? I'm using synchrotron data.
nandini
--- Von Dreele, Robert B. [EMAIL PROTECTED] wrote:
Nandini,
GSAS gives R(F^2) which is sometimes defined for
single crystal structure analysis. It can be used
Jennifer,
Yes. Start with SXTLDATA to read in the hkl file. It will ask for lots of stuff but
you will only really need h,k,l,Fo sig(Fo). Then go to EXPEDT to put in the rest of
the stuff (atom positions, etc.).
Bob Von Dreele
-Original Message-
From: Jennifer Anderson [mailto:[EMAIL
Dr Von Dreele,
The structure at room temperature was refined from neutron TOF. Now, I am using this
model to refine low temperature data from neutron CW. My sample has Cu-Cl-La-Nb-O.
Sincerely,
Liliana
-Original Message-
From: Von Dreele, Robert B. [mailto:[EMAIL PROTECTED]
Sent: Thu
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