[Ifeffit] Fitting XANES spectrun with standards

[adrien couet]

Hi all,

I am having some troubles when I fit XANES spectra with a library of
standards. The unknown spectrum has been processed (background removal,
normalization,...).

If I understand correctly the documentation, I have two ways to fit the
unknown spectra:

- using "fit this group" and I will get the best fit using my standards
library
- using "fit all combinations" and I will get all the different fit results
from the best to the worst.

However, it appears that the result given by "fit this group" does not
correspond to the best fit given by "fit all combinations" (it often
corresponds to a higher R factor fit), and thus "fit this group" does not
give me the best fit possible. Are these two fitting processes using a
different fitting algorithm?

I attached one example to this email. I am using a library of 8 different
Fe standards to fit the unknown spectra.

Thanks for your attention

-- 
Adrien Couet
Graduate Student
Dept of Nuclear Engineering, Penn State University
+1 814 865 9709
axc1019 at psu.edu
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