Electronic structure and optical properties of bare and coated C 60 molecules

Abstract

Ground state electronic structures of C 60 and metal coated C 60, modeled with the clusters Li 12C 60 and Li 32C 60, are analyzed within the local density functional approximation. The low-energy part of the linear-response spectra of a bare C 60, Li 12C 60 and Li 32C 60 is also studied. The Kohn-Sham molecular wavefunctions are used for the evaluation of dipole matrix elements and polarizabilities, and the effect of screening the oscillator strengths is found using a simplified RPA approach. For the Li-coated C 60 species the electronic level diagram shows correspondence to the C 60 level diagram but with new levels originating from Li close to the Fermi level. New structure in the oscillator strength distribution from the Li-coating is found at lower energy than the π plasmon of C 60 at about 6 eV.