[Ifeffit] Problems with GeO2

Andreas Schacht schacht at physik.uni-dortmund.de
Sat Jul 22 14:16:40 CDT 2006

Hi Leonardo,

thanks for your quick reply. I have read about the problem with the shift
vector and tried therefore several configurations, but none of them work
out. The data for the input file was taken from the "American Mineralogist
Crystal Structure Database":

Smith G S, Isaacs P B
Acta Crystallographica 17 (1964) 842-846
The crystal structure of quartz-like GeO2
Note: polymorph of argutite
4.987 4.987 5.652 90 90 120 *P3_221
0 0 .6666666666666
atom     x     y     z B(1,1) B(2,2) B(3,3) B(1,2) B(1,3) B(2,3)
Ge   .4513     0     0  .0076  .0067  .0042  .0034      0      0
O    .3969 .3021 .0909  .0192  .0142  .0083  .0118  -.004  -.003

The input file for FEFF was than created with webatoms and I allready
visualized the calculated coordinates and the results look like a
quartz-structure so I am not quite sure if this is the problem.
The FEFF-calculation itself was done with more than 100 atoms and as far I
can tell the calculated DOS doesn't look so bad compared to other
DFT-calculations of alpha-quartz GeO2.
So if someone has an idea what to try next...
Thanks again.



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