High energy resolution X-ray absorption spectroscopy study of uranium in varying valence states

High energy resolution X-ray absorption spectroscopy (XAS) study on U4+ (UO2), U5+ ([UO2Py5][KI2Py2]) and U6+ (UO2(NO3)2*(H2O)6) materials have been performed. We demonstrate the potential of this novel experimental technique for qualitative/semi qualitative and quantitative actinide speciation investigations and discuss its advantages over the standard XAS technique. For the first time a pre-edge feature in U L3 edge partial fluorescence yield X-ray absorption near edge structure (PFY-XANES) spectrum is observed and its origin explained by performing calculations with the FDMNES code based on the multiple scattering theory and the finite difference method. PACS numbers: 61.05.Cj, 78.70.Dm, 78.70.En, 71.20.-bJRC.E.6-Actinides researc