CORRELATION-EFFECTS IN SOLID C-60

The bandgap of solid C60 is found to be 2.3 +/- 0.1 eV. The on-site molecular C60 Coulomb interaction (U) as determined from the KVV C60 Auger spectrum is found to be 1.6 +/- .2 eV. This value of U is shown to be consistent with Frenkel type molecular excitons in the 1.5 - 2 eV range. These results lead us to suggest that doped C60 should be considered as a highly correlated system with U/W comparable to that in high T(c) cuprates. The Auger spectroscpoy results are consistent with a rather long range Coulomb interaction on a single bucky ball indicating that a Hubbard model is not suitable to describe the electronic structure of a C60 molecule.