[Ifeffit] Why different installations of Atoms generate different results?

[Tsuei, Ku-Ding]

Hi Bruce,

I am a novice of this community and actually have less than two weeks of 
experience using IFEFFIT (version 1.2.11 with iff_013 update) and its 
front end packages Demeter (version 0.9.11) and its predecessor Horae 
(Athena, Artemis etc. version 0.8.014) running under Windows 7 
Professional SP1. They are excellent software guiding me quickly into 
this EXAFS world. Thanks a lot.

However, I feel confused by viewing different results (chi(k)) 
calculated from three installations of Atoms, namely Atoms within 
(D)Artemis, stand alone (D)Atoms, and Atoms within the old Artemis. I 
then used the simplest Au.inp as the input for all. I checked the path 
outputs making sure the generated paths are identical and selected 
individual paths. To my surprise the chi(k) curves have different 
envelopes and magnitudes from 3 Atoms. It seems to me that chi(k) are 
calculated from the same feff6 program and should be identical from any 
installation; no FT range is involved to affect chi(R). Could you help 
clarify my confusion?

Perhaps the new Demeter can be improved further. It seems that only 
k^2*chi(k) is plotted in Atoms within (D)Artemis, and only k*chi(k) is 
plotted in the stand alone (D)Atoms by viewing the vertical labels in 
plots. There seems no obvious place I can change k-weighting like in the 
old Artemis. I have not been able to find where, such as Edit preference 
in the old Artemis, I can change the default parameters, or learn what 
parameters are used in doing FT (kmin, kmax) or window function and so 
on. I learn these preference parameters quickly owing to the extensive 
documents built-in side by side with "action tabs" in the old Artemis 
and the link to html documents in the old Athena. By the way, watching 
your videos is an excellent way to learn Demeter but I had to pause to 
search related projects or files to run side by side with videos; some 
links with video download sites could be very helpful.

Look forward to reading your answers and utilizing the more powerful 
Demeter. Thanks again.

Best regards,

Ku-Ding Tsuei
------------------------
Ku-Ding Tsuei, PhD
Associate Scientist
National Synchrotron Radiation Research Center
101 Hsin-Ann Road
Hsinchu Science Park
Hsinchu, TAIWAN 30076, ROC
email: tsuei at nsrrc.org.tw
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