Dynamical screening by d-electron in optical and virtual excitation in f-electron systems

Optical excitation spectra of the core-electron and the 4f-electron of CeSb are analyzed considering the screening by both the 4f and the 5d-electrons. As a direct evidence of the dynamical screening by the 5d-electron, the p-d antibonding peak is expected at about 10 eV higher binding energy than the main peak with about a half of intensity of the main peak. This peak explains the satellite seen in the experiment which has been attributed to the plasmon side band. Similar satellite is expected also in the core-level XPS of the Sb site due to the screening by the p-electron. The dynamical screening by the 5d-electron reduces the value of the p-f mixing. This reduction effect is verified also in the low frequency region by calculating the optical and magnetic excitations based on the renormalization group technic. The low energy fixed point belongs to the same class to that of the Kondo problem even when the d-f Coulomb interaction is included. (author)