Dramatic distortion of the 4d giant resonance by the C60 fullerene shell

The photoionization cross section for the endohedral Xe at C60 atom is investigated within the framework of representing the C60 by a delta-type potential. Results demonstrate that in Xe at C60, the 4d giant resonance is distorted significantly when compared with that of the isolated Xe atom. The reflection of the photoelectron waves by the C60 causes strong oscillations in the photoionization cross section resulting in the replacement of the Xe 4d giant resonance by four prominent peaks. The approximation of C60 by an infinitely thin real potential preserves reasonably well the sum rule for the 4d electrons but modifies the dipole polarizability of the 4d shell. (letter to the editor)