[Ifeffit] Fitting Problems via Artemis

[hsnuboy at ksu.edu]

Dear Norbert,

Thank you for your reply. About the DW factor, I think the problem may
be another scatterer. Due to the self adsoption, I use Dr. Booth's
correlation equation to correlate my data. Is that the way I obtain
minus DW factor? The other parameters work great, except DW factor for
about -0.001(the uncertainties is +/- 0.00094). Do you thinnk is that
possible cause by self absorption or other effects? Thank you for your
time.

Sincerely,

Yu-Chuan

On Fri, 24 Sep 2004, nobert.weiher at chem.ethz.ch wrote:

>Concerning the DW factor, you are right that it accounts for
>vibrational disorder in the sample (in the ideal case). If, however,
>your material has a high structural disorder by itself, DW factors
>might become high due to this. The general behaviour is that they
>should increase with temperature of the measurement. A negative value
>is physically not possible, and usually means that something is wrong
>with your fitting path. Possible things to check are
>- did you use proper reference paths (i.e. were they correctly
>computed by feff)
>- is it maybe another scatterer which contributes to the EXAFS at this
>part.