We report on the most complete investigation to date of the $4f$-electron properties at the $\gamma \mathrm{\text{−}}\alpha$ transition in elemental Ce by resonant inelastic x-ray scattering (RIXS). The Ce $2p3d$-RIXS spectra were measured directly in the bulk material as a function of pressure through the transition. The spectra were simulated within the Anderson impurity model. The occupation number $n_f$ and $f$ double occupancy were derived from the calculations in both $\gamma$ and $\alpha$ phases in the ground state. We find that the electronic structure changes result mainly from band formation of $4f$ electrons which concurs with reduced electron correlation and increased Kondo screening at high pressure.

• Received 16 November 2005

DOI:https://doi.org/10.1103/PhysRevLett.96.237403