Model calculations of local exciton levels in the C60 fullerene crystals doped with endohedral fullerides M@C60 Original Research Article

A three-dimensional cluster model with periodic boundary conditions is proposed to describe the coupling between the Frenkel and charge-transfer (CT) excitations of the C60 fullerene crystal. The model is applied to calculate the eigenstates of the crystals doped with endohedral fullerides. According to the results of previous calculations [J. Chem. Phys. 108 (1998) 3498], two groups of endohedral complexes are considered. For one group, the ionization potential of the fulleride differs from that of C60 by less than 1 eV; for the other group, the difference exceeds 1.5 eV. The calculations predict the existence of local levels with a substantial contribution of the host Frenkel exciton only for a single dopant belonging to the first group. Dopants belonging to the second group are predicted to produce low-energy local levels of guest-to-host CT provenance. Possible conceptual advantages of experimental investigation of these compounds are discussed.