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 5fn-5fn+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 state 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.
 

Journal of Applied Physics, 63 3676-9, 1988.