[Ifeffit] Low amp results

[Joji Kuniya]

Thank you so much for many experts replay.
Lithium tantalate crystal is R3c space group and actually have many hole at 
Li site . I think that Fe should be replaced to Li or implemented to the 
absent site. At first, I made the structure which was exchanged Li to Fe, 
but this structure was not fitted to the data. So that , I changed z value 
of Li of atoms on the input data to smaller and changed Li to Fe. I used 
default GDS parameters for the fitting because my knowledge of how-to 
manipulating GDS is not enough. I used 6 paths for the fitting. 1-3.4(1/k) 
range and kw=1 was used. Should I think about all paths? (Feff calculation 
makes 170paths). I received ZnO tutorial file from Dr.Fons last month. I 
studied the tutorials two or three times, but I could only have little 
knowledge what the meanings of the GDS parameter manipulations, because of 
my little knowledge of XAFS principals. I will read some XAFS tutorials. 
And, I will try some other structures and try more paths in fittings.
Thank you.
  ----- Original Message ----- 
  From: Joji Kuniya
  To: ifeffit at millenia.cars.aps.anl.gov
  Sent: Monday, May 28, 2007 7:51 PM
  Subject: [Ifeffit] Low amp results


  I analyzed EXAFS spectra of trace of Fe in lithium tantalate crystals. At 
first, I created the feff.inp file of LiTaO3. Then I changed central Li atom 
to Fe atom and added Fe atom at the Ta site. So that, the fitted results is 
good except amp(amp results is 0.3). I think that the model structure is 
good, but I can not understand why amp is too low. How do you think about 
this results? And, I tried to fitting treatment using GDS parameters. But, I 
do not know that the general method how to use the GDS parameters. Please 
tell me the general way of GDS manipulation. My PC runs under Win XP, and My 
Artemis runs under feff8 conditions. Thank you.
  Joji Kuniya


------------------------------------------------------------------------------


  _______________________________________________
  Ifeffit mailing list
  Ifeffit at millenia.cars.aps.anl.gov
  http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://millenia.cars.aps.anl.gov/pipermail/ifeffit/attachments/20070529/550ea8c5/attachment.html>