Abstrakt
The correlated band theory implemented as a combination of the local density approximation with the exact diagonalization of the Anderson impurity model is applied to PuO2. We obtain an insulating electronic structure consistent with the experimental photoemission spectra.
The calculations yield a band gap of 1.8 eV and a nonmagnetic singlet ground state that is characterized by a noninteger filling of the plutonium f shell ( n(f) approximate to 4.5). Due to sizable hybridization of the f shell with the p states of oxygen, the ground state is more complex than the four-electron Russell-Saunders I-5(4) manifold split by the crystal field.
The inclusion of hybridization improves the agreement between the theory and experiment for the magnetic susceptibility.