Mauro, If I do understand your question correctly, you may be asking how to handle a multiple of inequivalent sites in atomic clusters with N atoms, where each atom generates a unique sequence of single- and multiple-scattering paths. A possible solution is given in this article: D. Glasner and A. I. Frenkel Geometrical characteristics of regular polyhedra: Application to EXAFS studies of nanoclusters AIP Conf. Proc. 882 , 746-748 (2007). <https://exchange2000.bnl.gov/exchange/frenkel/Drafts/RE:%20%5BIfeffit%5D%20%5Bhowto%5D%20configurational%20average%20in%20EXAFS%20with%20FEFF.EML/XAFS13-Proc/clusters-geometry.pdf> The PDF is here: http://pubweb.bnl.gov/users/frenkel/www/XAFS13-Proc/clusters-geometry.pdf It is the same type of averaging and radial distribution analysis approach that you are proposing unless I misunderstood your question. Anatoly
________________________________ From: [EMAIL PROTECTED] on behalf of Mauro Rovezzi Sent: Tue 3/27/2007 9:38 AM To: Ifeffit-ML Subject: [Ifeffit] [howto] configurational average in EXAFS with FEFF 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 <[EMAIL PROTECTED]> PhD student - GILDA BM08 c/o ESRF (Grenoble, FR) _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit _______________________________________________ Ifeffit mailing list Ifeffit@millenia.cars.aps.anl.gov http://millenia.cars.aps.anl.gov/mailman/listinfo/ifeffit
