Semiclassical calculations of the cross section for electron-impact ionization of C-60

The semiclassical Deutsch-Mark (DM) formalism for the calculation of absolute cross sections for the single ionization of atoms has been extended to the calculation of the total single ionization cross section of the fullerene C-60. The present calculation uses a Mulliken population analysis in which the outermost 120 C-60 orbitals are represented as linear combinations of the atomic C(2s) and C(2p) orbitals and no contributions from the more tightly bound C(1s) electrons have been considered. Detailed comparisons are made with available experimental data. Calculated cross sections are considerably larger (and the cross section curve slightly different in shape) than the measured ones. This indicates that the DM formalism (along with other calculation schemes based on an additivity concept) cannot without appropriate corrections be applied to targets with a complex structure such as C-60.