The resonant inverse photoemission study (RIPES) at the Ce $4\overrightarrow{d}4f$ absorption edge of ${\mathrm{CeRh}}_3,$ ${\mathrm{CePd}}_3,$ and ${\mathrm{CeSn}}_3$ has been carried out. The RIPES spectra show the wide variety of the $4f$ electron character in these compounds, indicating the characteristic Kondo temperature and $4f$ electron number. The excitation energy dependence of $4f$-spectral resonance, especially in ${4f}^2$ final-state structure, indicates a large $4d-4f$ multiplet splitting and strict selection rule in the final state of the RIPES process. Constant final-state spectra of the $f^1$ final state show the $4f$ spin-orbit splitting components. A calculation is carried out by the impurity Anderson model with full multiplet effects and explains well the excitation energy dependence of the RIPES spectra.

• Received 6 October 1998

DOI:https://doi.org/10.1103/PhysRevB.60.5244