COLLECTIVE ELECTRONIC EXCITATIONS IN C-60 CLUSTERS

The large number of active electrons in a C60 cluster and the strong Coulomb interaction among them leads to a rich spectrum of collective states. States with total angular momentum up to L = 8hBAR have a strong collective character. The equivalent of both pi and sigma-plasmons in graphite are predicted. In the low-energy region a strong dynamical screening is obtained, in good agreement with measured absorption spectra. The theoretical results compare very well with photoexcitation and electron-energy-loss-spectroscopy data on gas targets in the high-energy domain.