Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

We report here the first detailed experimental and theoretical investigation of hexavalent uranium in various local configurations with high-energy-resolution fluorescence-detected X-ray absorption near-edge structure at the M4 edge. We demonstrate the pronounced sensitivity of the technique to the arrangement of atoms around the absorber and provide a detailed theoretical interpretation revealing the nature of spectral features. We show that for all local configuration analyzed, the main peak corresponds to non-bonding 5f orbitals, and the highest energy peak corresponds to anti-bonding 5f orbitals. Our findings are in agreement with the accepted interpretation of uranyl spectral features and embed the latter in the broader field of view where the spectra of a larger variety of U6+-containing samples are interpreted on the same theoretical ground.