Atomic-core dynamics and the electronic structure of some endo- and exohedral complexes of fullerenes with light elements

The atomic and electronic structure of some endo-, exo-, and endo-exohedral complexes of the fullerene C-60 with various guest atoms and molecules (He-n, H-2, and Li-2) are investigated using semiempirical and nonempirical quantum-chemical methods. The atomic core dynamics is studied by the method of molecular dynamics. It is shown that guest atoms and molecules in fullerene polyhedra acquire an orbital angular momentum due to the correlated motion of nuclei above the low-energy barriers of the potential surface within the carbon polyhedron even at low temperatures (from 4 to 78 K). The emergence of orbital angular momenta of nuclei of guest atoms and molecules is attributed to a change in the contribution of the orbital angular momentum of electrons to the potential surface of the complexes. The motion of Li ions in a polyhedron leads to blurring of the top of the valence band and to the emergence of a charge polarization wave in the carbon polyhedron. (C) 2000 MAIK "Nauka/Interperiodica".