Dear Nelson,
You can also often find structures of interest in the American
Mineralogist Crystal Structure database
(http://rruff.geo.arizona.edu/AMS/amcsd.php). Both of your phases are
listed numerous times in this data base, and you can download cif files.
The database is freely available.
Regards,
Dave
On 9/5/2014 1:34 PM, Leopoldo Suescun wrote:
Prezado Nelson,
You can find CIF files for both alumina and crocoite phases at the
Crystallography Open Database (www.crystallography.net
<http://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://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 no-one to ask
for advice it may be a painful path to walk alone but there are many
books that can be of help such as "The Rietveld Method" by RA Young or
"Fundamentals of Powder Diffraction and Structural Characterization of
Materials" by Pescharsky and Zavalij... but attending a Rietveld
course (such as ICDD Clinics for example) may be of help to start.
Finally, but maybe of advanced level, be very careful when extracting
weight percentages for both phases from your refinements, if you don´t
have perfect control or knowledge of particle sizes for both phases,
since the huge difference in absorption coefficients among them may
make microabsorption an issue on your quantification work.
Best of luck
Leo
2014-09-05 13:43 GMT-03:00 Nelson <nelson.dua...@ipn.pt
<mailto:nelson.dua...@ipn.pt>>:
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
alumina and 73-1332 for crocoite. I use software High score plus.
Can i use the 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 don´t have experience of rietveld analysis.
Thanks in advances
Best regrds
Nelson
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Dr. Leopoldo Suescun
Prof. Agr (Assoc. Prof.) de Física Tel: (+598) 29290705/29249859
Cryssmat-Lab./DETEMA Fax: (+598) 29241906*
Facultad de Quimica, Universidad de la Republica
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En pleno disfrute del Año Internacional de la Cristalografía 2014
(http://www.iycr2014.org ), (http://www.cristalografia2014.fq.edu.uy)
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David L. Bish
Department of Geological Sciences
Indiana University
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812-855-2039
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