EXCITONS IN SOLID C-60

Exciton levels in undoped, solid C-60 are calculated using a model Ham iltonian. We find excitation energies of 1.58 and 1.30 eV for the lowe st singlet and triplet exciton, respectively, in comparison with the m easured energies of 1.83 and 1.55 eV. Singlet and triplet states have similar energy diagrams, wherein exciton states having T-2g, T-1g, G(g ), and H-g Symmetries are separated by up to several tenths of an elec tron volt. As a function of crystal momentum? exciton energies exhibit dispersion from 20 to 40 meV. Theoretical pressure derivatives of exc iton energies are presented.