[Ifeffit] convergence of XANES for STO

[Feng Wang]

Hi Lena,

It is no suprising to see the change of the fine structure near the edge 
within a cluster of that size, because of the long mean free path of the 
photoelectron. 

You used a broadening of 0.2eV in your FEFF input, which should give you 
more details than your experiments. 

Good luck,

Feng


> 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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