Resonant X-Ray Emission Spectroscopy at the L3 Edge of Americium up to 23 GPa

Abstract

Resonant X-ray emission spectroscopy and X-ray absorption near-edge structure experiments have been performed on Am metal at the L3 edge as a function of pressure. The hypothesis that the Am valence change at high pressure is associated with a mixing of a 5f state with the 6d valence band is not substantiated by the experiments. Neither the measured RXES nor XANES exhibit additional features expected for mixed-valence. Only a small shift ¿ +2 eV of the L3 edge energy position and a decrease in white line intensity at high pressure is observed. The experimental results at higher pressure may be reproduced by increasing the 6d bandwidth and occupation, and increasing the 5f bandwidth without any change in occupation. Further progress should be directed towards experiments at the Am M edges to observe directly the 5f states.