4f-5dhybridization and theα-γphase transition in cerium

The α-γ phase transition in Ce metal is explained by 4f-5d hybridization effects. The α phase is identified with a state consisting of hybridized 4$f^0$ and 4$f^1$ configurations where, although the 4$f^1$ component is dominant, the local magnetic moment is quenched via strong 4f-5d hybridization of the order of ∼1 eV. Increased 4f-5d hybridization with decreasing volume stabilizes the α phase relative to the γ phase for small volumes. The pressure-volume and pressure-temperature diagrams have been calculated with use of this model, and the phase diagram of Ce has been well reproduced. The core-level photoemission, valence-band photoemission, and bremsstrahlung isochromat spectra of α- and γ-Ce have been calculated based on the same model, and good agreement with experiment has been obtained.