EXPERIMENTAL-EVIDENCE FOR 400-MEV VALENCE-BAND DISPERSION IN SOLID C-60

Angle-resolved electron distribution curves have been measured for two different excitation energies on heteroepitaxial C60(111) films. At HBARomega = 29 eV, the limited k(parallel-to) resolution together with broadening induced by vibronic excitations results in a weak dependence of the peak positions and line shapes of the photoemission features on the emission angle. We demonstrate that at the low photon energy of HBARomega = 8.1 eV the k(parallel-to) resolution becomes sufficient to resolve two bands in the feature derived from the highest-occupied molecular orbital which show a dispersion of the order of 400 meV.