Electronic structure of the light actinide oxides from electron spectroscopy (invited)

Abstract

The 4f core level spectra of ThO₂, UO₂, and NpO₂ are shown to be well described in the Anderson impurity model. The O(2p)-actinide (5f) hybridization is found to be very large. This leads to a new interpretation of the 7-eV satellite in the 4f spectrum, which corresponds to an antibonding 5f ⁿ-5f ⁿ⁺¹ final state, where n=0,2, and 3 for ThO₂, UO₂, and NpO₂, respectively. The resonance photoemission 4f spectrum is studied, and it is found that interference between different intermediate states is crucial for its interpretation. In particular, the photon energy dependence (CIS spectrum) is strongly influenced by these interference effects. In the 5f valence spectrum of UO₂ the theory gives a satellite, which is due to a split-off state caused by the large hybridization.