[Ifeffit] Phase correction not working in Athena

[Zimina, Anna (IKFT)]

Hi, Sebastian.

 

Normally you tick the "phase correction" and redo the FT of the data (click
the R button again) - usually the shift is first then seen.

 

Anna.

 

Von: Ifeffit [mailto:ifeffit-bounces at millenia.cars.aps.anl.gov] Im Auftrag
von Sebastian George
Gesendet: Mittwoch, 31. August 2016 15:06
An: ifeffit at millenia.cars.aps.anl.gov
Betreff: [Ifeffit] Phase correction not working in Athena

 

Dear all, 

 

I hope that I am writing this in the correct place, and if I am not, I
apologize. The problem I'm having is pretty much summed up in the Subject
line. I'm analyzing some experimental EXAFS data in Athena, and it seems
that ticking the "phase correction" box has no effect on my Forward Fourier
transform. Has anybody run into this problem, and if so, were you able to
fix it? The material I'm studying is amorphous SmCo. Could it be that having
multiple backscattering species or a lack of crystalline structure causing
problems for the phase correction? 

 

More generally, I'm wondering how exactly this phase correction is
determined anyway. If used, is it the sort of thing that can put the first
peak in my FT fairly close to the true nearest neighbor distance? Perhaps a
better phrased question is: when can the phase transformation be expected to
give a quantitatively accurate radial distribution (in terms of peak
positions), and when is it more likely to only be qualitatively useful?
Also, I would have assumed that a backscattering species would need to be
given in order to calculate the phase shift, but I haven't found anywhere to
do that. Have I missed something?

 

Thank you for any help in advance!

 

Regards,

Sebastian

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