PLASMON FINE-STRUCTURES IN MULTIPLE INELASTIC ELECTRON-SCATTERING OFFC-60 CRYSTALLITES

We report the observation of well-resolved fine structures in the main plasmonic band multiples of solid C60, as measured by reflection EELS . The various peak energies are correlated as pure overtones and combi nations of a fundamental set of plasmonic features, showing no evidenc e for anharmonicity. Focusing on the relative intensity of combination s and overtones, a pronounced dependence on crystalline order is found . This effect can be explained by the localization of some collective modes within the granular structures.