F-state occupancy at the γ-α phase transition of Ce-Th and Ce-Sc alloys -: art. no. 067402

Resonant inelastic x-ray scattering spectra were measured for a series of Ce solid solutions (Ce-Th and Ce-Sc) across the gamma-alpha phase transition. They reveal a well-defined feature associated with the 4f(2) configuration when the incident energy is tuned to the Ce L-3 preedge region. This component is normally hidden in x-ray absorption spectra because of lifetime broadening. The f(1)/f(2) ratio estimated by resonant inelastic x-ray scattering presents a sharp drop across the gamma-alpha transition and hysteresis as a function of temperature that closely resemble the magnetization loop. These measurements confirm recent dynamical mean-field theory calculations that unexpectedly predict significant double occupancy of f orbitals in the ground state.