Hi Matt, okay - I attached a chi.dat file with the EXAFS to fit and a FEFF input file with which I did the reference paths. I tried to fit the first shell with the first five paths which came out of the FEFF calculation. The problem was that the algorithm really went somewhere - no matter what paths or path combinations I used in the fit. The system is a VOHPO4 based catalyst and should have simply some 5-6 O atoms in the first shell. A comparison of the FT EXAFS with the literature looks reasonable. Maybe it is a problem of the correct bg subtraction? I really don't know this time. It might be a good idea to first do V2O5 or some similar compound. But unfortunately, I don't have spectra available. So if anyone has done V2O5 or something similar it would be great to hear of your experiences with this compound. One last word to the catalyst sample: These V cats are lousy for EXAFS (lots of similar scatterers in slightly different positions). So it might be that an out of phase problem is the main point here. Thanx for the help :) Norbert -- Dr. rer. nat. Norbert Weiher (norbertweiher@yahoo.de) Laboratory for Technical Chemistry - ETH Hönggerberg HCI E 117 - 8093 Zürich - Phone: +41 1 63 3 48 32