[Ifeffit] [howto] configurational average in EXAFS with FEFF

[Mauro Rovezzi]

Dear all,

I would like your point of view on how to approach configurational
average in EXAFS analysis with FEFF (let's not consider GNXAS for the
moment).

In particular, I'm trying to combine ab-initio DFT numerical simulations
with EXAFS for doped semiconductors where in the minimized cluster there
are N absorbing atoms.

Usually I don't use the CFAVERAGE card because fractional degeneracies
are not taken into account and, to have a qualitative analysis, I
calculate an "extended"-XANES (up to 8.0 A^-1) for each cluster - where
each absorbing atom is shifted to (0,0,0) - and then I average over all
single-cluster signals.

Well, at this point my question is: how to proceed in the quantitative
analysis with Ifeffit? In fact, considering only single-scattering
expansion for all the clusters the result could be seen as a radial
distribution for each scattering pair where the integral gives the
coordination number and the FWHM a structural Debye-Waller factor. How
to combine these informations?

Thanks for the answers,
Mauro

-- 
Mauro Rovezzi <rovezzi at esrf.fr>
PhD student - GILDA BM08 c/o ESRF (Grenoble, FR)