Theoretical Study of Electronic Structure of Charged Fullerenes

Abstract

The properties of excited short-living electron quantum levels of positively charged ${\text{C}}_{60}^{+Z}$ fullerenes are numerically investigated with the help of the density functional theory (DFT) packages Quantum Espresso, ORCA, and VASP. Earlier, the existence of the volume-localized electron states for neutral and charged fullerenes was demonstrated analytically by making use of the model potential approach based on the unique quasispherical geometrical shape of C60. Here, we revisit this issue by verifying numerically the existence of volume-localized states and by calculating physical parameters of all electronic states with a special focus on highly charged fullerene ions. The ionization potentials of ${\text{C}}_{60}^{+Z}$ are calculated and compared with available experimental data. The photoionization cross-sections for neutral fullerene using wave functions are obtained by making use of DFT codes. We demonstrate that lifetimes of excited states vary in the range ${10}^{-11}÷{10}^{-4}$  s, and for the volume-localized levels, lifetimes are longer than those for the surface-localized states.