Experimental evidence for 400-meV valence-band dispersion in solid C60

Angle-resolved electron distribution curves have been measured for two different excitation energies on heteroepitaxial C60(111) films. At ħω=29 eV, the limited k∥ 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 ħω=8.1 eV the k∥ 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.