Hello.
I am trying to fit the EXAFS data of Pt-Ni (around 1:1) alloy nano particles on oxide support.
- How can i fit the Pt-Ni metallic peak which is a bit different from Ni metal and Pt metal peak.
- Additionally, the cif file i have does not work. A message of "atoms is unable to use crystal data which has sites of partial occupancy" is seen. How can i deal with my cif file?
- Please let me know if you have a similar cif file which i can use to fit my EXAFS data.
I found four entries in the COD (Crystallography Open Database ):
http://crystallography.net/cod/1523344.cif
http://crystallography.net/cod/1523590.cif
http://crystallography.net/cod/1537974.cif
http://crystallography.net/cod/1538610.cif
best regards
Dear Yukwon, I feel that, as both Ni and Pt are fcc metals, that the resulting unit cell will as well be fcc (space group 225) - this is exactly what can be found in the cif-files provided by Götz Schuck ! The only difference for the pure metals is that the origin of the unit cell is populated by both Pt and Ni, summing up to "1", and a slightly different lattice parameter due to the different sizes of Pt and Ni (lattice constants for pure Pt is 3.91 Angst., Ni has 3.52 Angst.). According to rules that apply for alloys, the average lattice constant can be determined by Vegards law, i.e. depending on the actual concentrations of Pt and Ni. So the problem should be treated ...
Best regards, Dirk
What you may try is the solution proposed by Bruce Ravel and Scott Calvin on the Artemis/Demeter web-pages, I tried this out, and it worked out well:
https://bruceravel.github.io/demeter/artug/extended/dopants.html
Keep us updated about your progress, best regards, Dirk
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