[Ifeffit] convergence of XANES for STO

[Lena Fitting]

Dear all,

I have a question regarding the convergence of XANES calculations. I'm 
currently focusing on the O-K edge of perovskite oxides, in particular 
SrTiO3 and found that there are still fine-structure changes for large 
(9.5Å) clusters. Attached is my *.inp file for the 9.5Å cluster and a 
summary of the XANES for increasing cluster sizes from 6.5Å to 9.5Å. You 
can see that there are still significant changes as the cluster size is 
increased from 8.5 to 9.5Å. In particular, I find a double peak feature 
in the first 5eV after the edge onset, which is not observed 
experimentally. Do you have any suggestions how to obtain a better 
convergence?

Secondly, if you compare the simulated XANES with experimental results 
(see attachment: EELS STO.png), I'm not able to match all three main 
peaks, even by scaling the energy scale. Are the deviations I'm seeing 
within the accuracy of FEFF or do I need to improve my *.inp file?

Best regards,
Lena

---------------------------------
Lena Fitting Kourkoutis
E13 Clark Hall
Cornell University
Applied and Engineering Physics
Ithaca, NY 14853

phone: 607-255-0654
e-mail: lf56 at cornell.edu
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