Theory of variation from localized to itinerant magnetism in cubic intermetallic actinide compounds

The Fermion excitation spectrum of a cubic crystal of actinide ions with partly filled 5f shells is derived. The crystal field and intraatomic interactions are assumed to be large compared with the one-electron interatomic hopping energy, so that Hubbard's ''atomic representation'' is valid. The magnetic moment, the magnetic susceptibility, and the fractional valence of the actinide ions are calculated as functions of the temperature, the external (or internal) magnetic field, and the f-f hopping energy. Assuming that the latter energy increases with decreasing lattice constant, results in qualitative agreement are found with the variation from localized to itinerant magnetic behavior observed in intermetallic actinide compounds