C60 fullerene as a pseudoatom of the icosahedral symmetry

Unique features of the electronic structure and spectra of the C-60 (I-h) fullerene and its ions related to the icosahedral symmetry are discussed. The so-called 'accidental' degeneracy of terms in the open electron shells g(N) and h(N) (corresponding to four- and fivefold degeneracy of molecular orbitals, respectively) and the abnormal ('non-Bethe') splitting of terms in the h(N) configuration are considered. The need to describe these terms arises in studies of ionized and excited states of the C-60 molecule and its derivatives. A novel approach to the description of C-60(m +/-) ions based on representation of the C-60 (I-h) fullerene as a (pseudo)atom of icosahedral symmetry is considered in detail. The approach involves an expansion of the molecular orbitals of C-60 in terms of the atomic orbitals centred at the origin (at the centre of the C-60 molecule) and a multiple expansion of the electron repulsion. The energy spectra of the fullerene and C-60(m +/-) ions, the magnetic moments and optical dipole transitions are considered. The results obtained are compared with those of ab initio calculations and with the available experimental data. The bibliography includes 119 references.