[Ifeffit] Re: phase shift

[Bruce Ravel]

On Friday 14 July 2006 03:03, you wrote:
> I'm using Athena for fitting my EXAFS data. I have a problem: I need the
> phase shift corrections for Ni as a function of the photon energy in the
> range (38-44) keV. In fact, I'm studying the La K edge in LaNi_5 and so I
> have to put the phase correction relative to the Ni-La scattering. May you
> help me, please? Thank you and excuse me.

Antonio,

This is the sort of question that you should consider asking on the
ifeffit mailing list.  That way, when I'm out of town, as I was last
week, someone else might be able to answer your question.
   http://cars9.uchicago.edu/mailman/listinfo/ifeffit/


I believe that the thing you are looking for is answered in the
documentation for both Ifeffit and Feff.  Here is a link from the
Feff6 document that explains what the columns are in a feffNNNN.dat
file:

  http://feff.phys.washington.edu/feff/Docs/feff/feff6-6.html#ss6.7

The language in that document is a bit cryptic, but you can see that
the third and fourth columns of that file are the magnitude and phase
of the effective scattering function for the path.

Here is a link where Ifeffit explains what happens you you directly
read a feffNNNN.dat file:

   http://cars9.uchicago.edu/~ifeffit/refman/node24.html

Again, we see that the third and fourth columns of the file contain
the magnitude and phase of the effective scattering function.

So it would seem, by my understanding of your question, that you need
to find the feffNNNN.dat file for the scatterer you are interested in
and use the fourth column of that file.

HTH,
B


-- 
 Bruce Ravel  ---------------------------------------------- bravel at anl.gov

 Molecular Environmental Science Group, Building 203, Room E-165
 MRCAT, Sector 10, Advanced Photon Source, Building 433, Room B007

 Argonne National Laboratory         phone and voice mail: (1) 630 252 5033
 Argonne IL 60439, USA                                fax: (1) 630 252 9793

 My homepage:    http://cars9.uchicago.edu/~ravel 
 EXAFS software: http://cars9.uchicago.edu/~ravel/software/exafs/