Photoionization of Ce$^{3+}$ and Ce$^{3+}$@C$_{60}$

Photoionization of the Ce$^{3+}$ and Ce$^{3+}$@C$_{60}$ in the energy region 100-150 eV has been studied using our recently developed random phase approximation with exchange method and model potential for the C$_{60}$ fullerene. Comparison of the ressults of the Ce$^{3+}$ photoionization with a recent measurement confirms the value of the measured cross section for Ce$^{3+}$ and indirectly supports the observed suppression effect of the carbon cage in the endohedral fullerene Ce@C$^+_ {82}$ photoionization. Our calculation of the Ce$^{3+}$@C$_{60}$ photoionization process demonstrates both the suppression and the resonance effect of the C$_{60}$ shell.