ELECTROABSORPTION SPECTRUM OF BUCKMINSTERFULLERENE - EVIDENCE FOR THE EXISTENCE OF CHARGE-TRANSFER STATES

Theoretical considerations suggest that the buckminsterfullerene crystal may have a distinct manifold Of excited charge transfer (CT) states. In the present paper, the energies of these states are estimated and their probable properties are discussed. The recently published electro-absorption spectrum of C60, originally interpreted in terms of a set of bands originating from Frenkel (intramolecular) excitations, is demonstrated to contain considerable contributions from the CT states. The CT states are located at about 2.7 and 4 eV, in excellent agreement with theoretical estimates. Some other consequences of the existence of excited CT states are predicted that are open to experimental verification.