Hi JA, I'll put in my two cents on some of these questions, although in some cases it's a matter of personal taste: At 03:16 PM 9/22/2006, you wrote:
I have read Phase corrected Fourier transforms in Athena manual and now I have a big doubt, ¿phase correction or not in a publication?
I vote not. :) Most of the time, phase corrections are desired for cosmetic reasons, to make the FT look more like a radial distribution function. But the FT is never a RDF, and so an attempt to make it look like one may mislead some readers without much experience in EXAFS. Also, adding a phase correction necessitates a discussion of what method for applying the phase correction was used, which complicates the publication. On the other hand, I'm less opposed to using phase-correction for presentations and posters intended for a non-EXAFS audience, although I still don't do it. Like I say, this is a matter of personal tatse.
I have high correlations between ss and SO2, and deltaR and deltaE. I tried different fits but I can not eliminate them, then...is the fit wrong?
No, this does not mean the fit is wrong! It is hard to eliminate the correlations you describe. And the algorithm used by Ifeffit to calculate the uncertainties works in such a way that you don't have to worry about correlations adding extra uncertainty beyond what's reported. High correlations do help you, as the person doing the fits, diagnose why an uncertainty might be high. If you find the uncertainty for deltaR is too high to say anything useful about a bond length, for example, then check the correlation with deltaE0. If the correlation is high, there are a number of things you can try to reduce the correlation, and, hopefully, the uncertainties: fitting multiple k-weights, fitting more coordination shells, etc..
Sorry for these easy questions but I am a novice in XAFS.
That's one of the things this list is for... --Scott Calvin Sarah Lawrence College