Hi everybody
I have run 14 samples (each 4 times) on the beamline, and I'm looking for a shift in the oxidation state of Uranium (4+ to 6+). I'm not sure and can't seem to find any literature on how significant the shift must be to prove anything.
That surprises me. The literature on XAFS studies of uranium valence is enormous, much of it written by people who read this mailing list. Hopefully one of those fine people will offer up a wealth of suggestions for places to look.
You may have a look at the following papers: Sturchio et al, Science, vol. 281, p. 971 (1998) Hudson et al., Phys. rev B., vol. 52, p 13815-13826 (1995) Farges et al., Geochim. Cosmochim. Acta, vol 56, p. 4205-4220 (1992) (sorry for the geochemistry bias) The edge position is in fact little discussed. More people prefer to refer to the presence of a shoulder at ~10-20 eV after the main peak, which results from mutliple scattering within the UO2 linear motif. Best regards - Michel