Look at peaks at lower 2theta, e.g. 10 deg.
.
Peter Y. Zavalij, Ph.D.
Director, X-ray Crystallographic Center (XCC)
Department of Chemistry and Biochemistry
University of Maryland, College Park, MD 20742
XCC Website <https://w
Peter
Peter Y. Zavalij, PHD
Director - X-ray Crystallographic Center
University of Maryland,
College Park, MD 20742
On Tue, Feb 21, 2023 at 1:11 PM Toby, Brian H. wrote:
> I am going to make the comment that (A) neutral atom form
Now Topas has anisotropy built in the GUI version too. No script is needed.
Peter
Peter Y. Zavalij, PHD
Director - X-ray Crystallographic Center
University of Maryland,
College Park, MD 20742
On Tue, Aug 2, 2022 at 9:16 AM
solution).
Peter
Peter Y. Zavalij
Director - X-ray Crystallographic Center
University of Maryland,
College Park, MD 20742
On Wed, Aug 29, 2018 at 12:38 PM David Elbert wrote:
> Absolutely important that people understand that
>From my experience some transition metal oxides, like MoO3, WO3 etc, turns
slowly blue under X-tay, assumedly due to metal reduction.
Peter Zavalij
On May 22, 2017 10:00 AM, "Payzant, E. Andrew" wrote:
> You can run into “interesting” behavior with metastable phases. I once ran
> a sample that
published data not included in any
database.
Peter Y. Zavalij
Director - X-ray Crystallographic Center
University of Maryland, College Park, M
aryland
On Tue, Jan 10, 2017 at 10:12 AM, Shay Tirosh wrote:
> Dear retrievers
&g
it
is basically beyond the limt of the methods.
Peter
Dr. Peter Y. Zavalij
Director - X-ray Crystallographic Center
University of Maryland, College Park, MD 20832
On Wed, Jul 27, 2016 at 1:07 PM, "Łukasz Kruszewski&q
FYI: Kristallografiya was translated into English as Soviet Physics
Crystallography and can be found in many western libraries. Although I am not
sure what year they started translation. Could be after 1966.
Peter Z.
__
Peter Zavalij
Director, X-ray Crystallog
How about "reciprocal methods" as opposite to "direct methods" which work in
reciprocal space?
Peter
__
Peter Zavalij
Director, X-ray Crystallographic Center
University of Maryland, College Park, MD 20742
http:/www.chem.umd.edu/crystallography
-Origina
To those who does not know:
Here is absolutely legal way to download cif file(s) of published structure
from CCDC:
http://www.ccdc.cam.ac.uk/Community/Requestastructure/Pages/Requestastructure.aspx
Peter Zavalij
__
Director, X-ray Crystallographic Center
University of
I started purging graphite mirror (and all shutters) with dry nitrogen gas a
few years back. No problem since then.
Peter
Peter Y. Zavalij
X-ray Crystallographic Center
University of Maryland
Ph/fax: (301)405-1861
www.chem.umd.edu/crystallography<http://www.chem.umd.edu/crystallography>
<mailto:matt.beek...@oit.edu>]
Sent: Tuesday, 17 September 2013 2:08 AM
To: Peter Y. Zavalij; Alan Coelho;
mariomac...@tux.uis.edu.co<mailto:mariomac...@tux.uis.edu.co>;
rietveld_l@ill.fr<mailto:rietveld_l@ill.fr>
Subject: RE: Instrumental resolution function
Alan, Peter,
Would
.beek...@oit.edu]
Sent: Monday, September 16, 2013 12:08 PM
To: Peter Y. Zavalij; Alan Coelho; mariomac...@tux.uis.edu.co; rietveld_l@ill.fr
Subject: RE: Instrumental resolution function
Alan, Peter,
Would you mind briefly elaborating on the procedure used to "fit tube tails?" I
personally have
unday, September 15, 2013 10:05 PM
To: Peter Y. Zavalij; mariomac...@tux.uis.edu.co; rietveld_l@ill.fr
Subject: RE: Instrumental resolution function
Hi Peter, Mario
I happen to have a Ni filter, Cu, LaB6 pattern that has a very similar look to
the one sent by Mario. Probably best to look at the
Hi Mario,
The shoulder you observe is what's left from "white" after it is cut off by
beta-filer. You could check the absorption edge of Ni and it is right at the
shoulder you observe.
Peter
__
Peter Zavalij
X-ray Crystallographic Center
University of Maryland
Col
Maxim,
Generally bond length are not temperature depended (correct me if I am wrong).
So you don't have to do anything if non-ambient means different temperature but
I am not sure about pressure etc.
Peter
__
Peter Zavalij
X-ray Crystallographic Center
University o
At the end it is all wrong as we don’t refine individual electrons but
restrained groups that are called “atoms” which are extrapolated with some
average function calculated for free, unbounded atom.
Peter Zavalij
From: rietveld_l-requ...@ill.fr [mailto:rietveld_l-requ...@ill.fr] On Behalf Of
What software is used to convert neutron data in *.bt1 format to any
commonly used format, e.g. GSAS?
Thanks
Peter Zavalij
X-ray Crystallographic Center
University of Maryland
College Park, MD
Office: (301)405-1861
Lab: (301)405-3230
Fax: (301)314-9121
Another book on powder diffraction and rietveld refinement partially based
on GSAS with real examples to follow up the text also describes variety of
quantitative analyses:
http://www2.chem.umd.edu/facility/xray/FPDSCM2.htm
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Center
Department
Brian,
Your definition of Z makes perfect sense (not counting molecular crystals).
Except it's better to include partially occupied sites too assuming ( for Z
calculation only) that they are fully occupied. For molecular crystals it's
more complicated as distance should be calculated to account fo
One of the reasons could be preferred orientation. If this is the case, one
could derive orientation axis from the ellipsoids.
Peter Zavalij
X-ray Crystallographic Center
University of Maryland
College Park, MD
Office: (301)405-1861
Lab: (301)405-3230
Fax: (301)314-9121
-Original Message--
That's right. LP refinement works just fine within TOPAS but angular range
as wide as possible is needed. If it is up to 140-150 deg. 2thteta LP does
not correlate much with thermal parameters. Refined LP is not exact but very
close.
Peter Zavalij
X-ray Crystallographic Center
University of Mary
Well... the situation with LP is not so simple. Using TOPAS for refinement
data collected on D8 advance with Ni-filter and LynxEye detector I observe
the following:
- For all samples LP=0 is OK and gives the best fit as it should be by the
book.
- HOWEVER for LaB6 standard LP=0 yields very poor fi
Are these "flavored" comments appropriate for scientific discussion?
Peter Zavalij
-Original Message-
From: Smirnova Olga [mailto:olga.smirn...@hw7.ecs.kyoto-u.ac.jp]
Sent: Sunday, March 08, 2009 5:58 AM
To: Brian H. Toby; rietveld_l@ill.fr
Subject: Re: background subtraction R values
121
From: Beekman, Matthew [mailto:mbeek...@cas.usf.edu]
Sent: Saturday, March 07, 2009 7:20 PM
To: Peter Y. Zavalij; rietveld_l@ill.fr
Subject: RE: cRs
Hello all,
A quick question regarding the background subtracted R values:
In the .LST file, GSAS gives two sets of values for
There are others important criteria of refinement quality implemented in
many software but rarely analyzed or published. These are Rp' and Rwp'
calculated with background subtracted from both observed and calculated
data. They are especially important when dealing with high background cases,
e.g. F
Dear All,
Does anyone know how to set geometric restraints in TOPAS or where to find
how to do this?
Thanks,
Peter Zavalij
X-ray Crystallographic Center
University of Maryland
College Park, MD
Office: (301)405-1861
Lab: (301)405-3230
Fax: (301)314-9121
Kurt,
It looks like incorrect step size (difference between actual step size and
one that is written in the file) or incorrect distance to the detector. The
later may incorrect step size if detector is PSD.
I have similar situation with much smaller difference in peak position but
the shift (diff
FYI: 2nd edition our powder diffraction book has been just released
(paperback):
"Fundamentals of Powder Diffraction and Structural Characterization of
Materials. 2nd Edition"
Vitalij K. Pecharsky & Peter Y. Zavalij, Springer 2009.
See Springer webpage www.springer.com/978-0-387-0
Bob,
I have quick question about Marquardt Damping in GSAS:
Is this multiplier for diagonal elements of a normal equation matrix?
Thanks,
Peter Zavalij
Kurt,
An old way used for alloys is:
grease the surface of the sample holder (preferably backgroundless) with
some sticky stuff and sieve the powder onto it. The particles will fall down
and stuck at random orientations, unless they are large plates or needles.
Peter Zavalij
Director, X-ray Cry
What is current home page of the Rietveld users' mailing list?
Links that I have are either not valid or mirrors.
Many thanks,
Peter Zavalij
Director, X-ray Crystallographic Center
Department of Chemistry and Biochemistry
091 Chemistry Building
University of Maryland
College Park, MD 20742-4454
Does anyone know how to tell Rietica to account for background (from sample
holder, film, etc.) stored in separate file?
Rietica can do it but there is no much about how to set it up in the manual.
Thanks,
Peter Zavalij
As the matter of fact there is "print options" button in "LS control: tab.
Click the button and select what information you want to see in the listing
file.
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Center
Department of Chemistry and Biochemistry
091 Chemistry Buil
Davide,
Could you perform Rietveld refinement using combined neutron and x-ray data?
This would increase accuracy and the question what is better would
disappear. Basically all you need is both data done at the same temperature.
Also look at neutron and x-ray scattering factors. The neutron scatter
Dear Dr.Pukazhselvan,
In order to answer your question more information is needed:
Do all NaAlH4 peaks split?
Which peaks split more low angle or high angle?
Is intensities ratio of split peaks the same over whole angular range?
Peter Y. Zavalij
Director, X-ray Crystallographic Center
Try out Pow_DLL: http://users.uoi.gr/nkourkou/powdll.htm
It converts practically anything into anything.
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Center
Department of Chemistry and Biochemistry
091 Chemistry Building
University of Maryland
College Park, MD 20742-4454
Phone: (301
; when you choose "Insert
symbol". You could create shortcut to this bar and insert it before 1
"P¯1"but also you need to select this bar and make font condensed by about
6 pt. The crystallographic 1bar looks like this: 1 .
Peter
Dr. Peter Y. Zavalij
Director, X-ray Crystal
contrast (e.g. Mo) may help for
> that particular mix but probably won’t completely solve it.
>
> Pam
>
> *From:* Peter Y. Zavalij [mailto:[EMAIL PROTECTED]
> *Sent:* November 15, 2007 9:07 PM
> *To:* rietveld_l@ill.fr
> *Subject:* Amorphous content
>
> Hi,
&g
Ross,
The link to The Gem Dugout X-ray Diffraction Products is
http://www.thegemdugout.com/products.html.
The provide several reference specimens for affordable price, e.g. LaB6 -
$10/g.
And other diffraction products.
Peter
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Laboratory
Hi,
I am trying to determine amorphous content using Rietveld refinement and
internal standard. However resulting content of amorphous phase is really
unrealistic.
Moreover testing the method using standards with known amorphous content
does not clarify the situation. For example ZnO (NIST, 95% c
Tom,
We just replaced Gobel mirror that had the same problem/symptoms. Now we are
back to normal intensity.
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Laboratory
Department of Chemistry & Biochemistry
091 Chemistry Building
University of Maryland
College Park, MD 20742-4454
P
Try American Mineralogist Crystal Structure Database at:
http://rruff.geo.arizona.edu/AMS/amcsd.php
or simply Google.
Dr. Peter Y. Zavalij
Director, X-ray Crystallographic Laboratory
Department of Chemistry & Biochemistry
091 Chemistry Building
University of Maryland
College Park, MD 20742-
the as plotted data.
R.B. Von Dreele
IPNS Division
Argonne National Laboratory
Argonne, IL 60439-4814
-Original Message-----
From: Peter Y. Zavalij [mailto:[EMAIL PROTECTED]
Sent: Tuesday, July 18, 2006 1:52 PM
To: rietveld_l@ill.fr
The best (not the fastest) way is to import observed and ca
The best (not the fastest) way is to import observed and calculated plots
from CIF file into Excel spreadsheet and then do to the plot whatever is
desired. Reflections can be shown as error but using imported 2theta.
I have template that does scaling, etc. automatically (to some extend).
Peter Zav
Very probably you should refine preferred orientation 0,0,1. If it take
place you'll see improved adp's.
Dr. Peter Y. Zavalij University Crystallographer
Materials Research Center, SUNY at Binghamton
Tel: (607)777-4298Fax: (607)777-4623
E-mail:[EMAIL PROTE
You could do it approximately by introducing atom type with proper seq.
number (no. of electrons).
For example if you have Fe (26 electrons) with 50% occupancy you could use
Al (13 electrons).
It is good enough for powder pattern calculation.
Peter Zavalij
-Original Message-
From: Ana I
Windows 2000 does allow to associate many program to the same extension
using "Advance" button.
Dr. Peter Y. Zavalij University Crystallographer
Materials Research Center, SUNY at Binghamton
Tel: (607)777-4298Fax: (607)777-4623
E-mail:[EMAIL PROTECTED]
http://materials.bing
I have installed the last one and it's working fine under W2000
Dr. Peter Y. Zavalij University Crystallographer
Materials Research Center, SUNY at Binghamton
Tel: (607)777-4298Fax: (607)777-4623
E-mail:[EMAIL PROTECTED]
http://materials.binghamton.edu/zavalij
-Original Me
"Crystal structure ... is the properties ..."
It does not sound right but "very exiting "science"" is
to find link between the crystal structure and the properties...
Peter Zavalij
-Original Message-
From: E. K. Akdogan [mailto:[EMAIL PROTECTED]]
Sent: Thursday, March 29, 2001 4:29 PM
To
It is the closest much to your compound:
La1.5Ba1.5Cu3O7.2
Izumi et al. Japan. J. Appl. Phys., Part 2. 27 (1988) L824-L826.
-Original Message-
From: S. Nagesh Kini [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, March 27, 2001 8:45 PM
To: [EMAIL PROTECTED]
Subject: La336
I am looking for a
This is strange but Atoms 5 works fine under w2k on my PC.
-Original Message-
From: jools [mailto:[EMAIL PROTECTED]]
Sent: Saturday, December 02, 2000 5:24 AM
To: [EMAIL PROTECTED]
Subject: Atoms 5.0 and Win2000
Does anyone have any experience of getting Atoms v5.0 to run under win2k
pr
To my recollection it is AlB2 structure type:
sp.gr. P6/mmm, a=3 A, c=3.2 A
Al in 0,0,0
B in 1/3,2/3,1/2
Peter Zavalij
-Original Message-
From: Anthony Manerbino [mailto:[EMAIL PROTECTED]]
Sent: Thursday, November 23, 2000 11:54 AM
To: '[EMAIL PROTECTED]'
Subject: TiB2 crystal structure
Well, I don't like having computers for every possible OS
Dr. Peter Y. Zavalij University Crystallographer
Materials Research Center, SUNY at Binghamton
Tel: (607)777-4298Fax: (607)777-4623
E-mail:[EMAIL PROTECTED]
http://materials.binghamton.edu/zavalij
-Original Me
You may use comand line (F4), for example:
V and O and Mn and ELC=3
will give you all compounds containing only V, Mn and O.
See printed manual for other posibilirties.
-Original Message-
From: Habib Boughzala [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 21, 2000 12:05 PM
To: [EMAI
Same happens on Windows 2000. Mouse does not work even with DOS mouse
installed.
So I use no mouse. It is still possible...
-Original Message-
From: Davide Levy [mailto:[EMAIL PROTECTED]]
Sent: Tuesday, November 21, 2000 4:30 AM
To: [EMAIL PROTECTED]
Subject: RETRIEVE
Is there anybody w
Copyright problem is very important but I have one practical question. Does
anyone know how to make ICSD DOS based search
program works under Windows2000? Actually not search program
itself but mouse.
Dr. Peter Y. Zavalij University Crystallographer
Materials Research Center, SUNY at Binghamton
The equation (2) is nothing else but specimen shift in the Bragg-Brentano
geometry.
> I have a question concerning the systematic line shifts due to sample
> off-centering in the Debye-Scherrer-geometry. The shift D2Theta due to an
> eccentricity e in the incident beam direction is always given a
Unfortunately, it is impossible to determine absolute configuration from
powder data due to reflections overlapping.
- Original Message -
From: Yara Ramirez Quiroz <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Monday, April 05, 1999 9:14 PM
Subject: enantiopure compounds
>
> Hello
Yes, it was and still is common to remove some reflections from single
crystal data because of various more or less reasonable reasons but
I never heard somebody applying it to powder especially Rietveld data...
It makes no sense at all...
Dr. Peter Y. Zavalij University Crystallographer
aks, when beam is wider than sample;
- preferred orientation;
- extinction;
- PSF;
- sample transparency;
- alpha1/alpha2 ration;
- etc, etc.
- and of course almost everything that affects single crystal data too...
Dr. Peter Y. ZavalijUniversity Crystallographer
Materials Research Center,
I do not know bout Lij but Uij can be negative -- However only when "i" is not equal
"j".
Uii should be positive and greater than 0 to make physical sense. Moreover,
there are other restrictions too and I can find them if you are interested.
Dr. Peter Y. ZavalijUnivers
.
Dr. Peter Y. ZavalijUniversity Crystallographer
Materials Research Center, SUNY at Binghamton
Ph/Fax:(607)777-4623 E-mail:[EMAIL PROTECTED]
http://imr.chem.binghamton.edu/zavalij/zavalij.html
63 matches
Mail list logo
