  Optical absorption spectra of C60^6- are theoretically investigated in order
to analyze the optical properties of alkali metal doped fullerites A6C60. We
use a tight binding model with long ranged Coulomb interactions and bond
disorder. Optical spectra are obtained by the Hartree-Fock approximation and
the CI method. The Coulomb interaction parameters which are relevant to the
optical spectra of A6C60 are almost the half of those of the neutral C60. The
reduction of the effective Coulomb interactions is concluded for the heavily
doped case of C60.
