Hi Juejing,

Sorry for the trouble. It's hard to guess from the screenshots alone - if only we had a Project file you could send (soon, soon).

One thing I see is it looks like the Feff calculation you're using was done at the U K-edge. Is that correct? Is the data U K-edge too?

I don't know if that would completely explain the difference, and Mike's suggestion of looking at the coordination number is a good idea.

XAS Viewer writes a "feffit script" in your user folder (C:\Users\jiuju\larch\xas_viewer\feffit_script.lar). Compared to the GUI form, that's a little bit cryptic and formal, but it is also what the program is really doing. If the suggestions above don't help clarify the problem, can you post that?

On Fri, May 20, 2022 at 7:35 PM <juejing.liu@gmail.com> wrote:

Hi,

I am recently trying to use Larch to fit XAS spectra of uranium compounds (e.g., UO2, using an existing CIF file). I did not achieve a good fit and the amplitude of the model is way lower than the data. Then I tried to plot the uranium oxygen 1^st path with all 8 atoms a sigma2=0.001 by using the plot model function. The resulting scattering peak is still far lower than it should be (images below). Did I do something strange with the program?

The Larch version I used was 0.9.59. I can send the cif file and the UO2 data I used if necessary.

Best,

Juejing

Juejing Liu
Guo Group
Materials Science and Engineering program
Alexandra Navrotsky Institute for Experimental Thermodynamics

Washington State University
Pullman, WA 99164-4630
Office: Fulmer Hall, Room 630
Phone: 208-206-7304

_______________________________________________
Ifeffit mailing list
Ifeffit@millenia.cars.aps.anl.gov
http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
Unsubscribe: http://millenia.cars.aps.anl.gov/mailman/options/ifeffit

--Matt