ELECTRONIC EXCITATION OF C-70 IN THE GAS-PHASE BY ELECTRON-ENERGY-LOSS SPECTROSCOPY

Electron energy loss spectroscopy of the C-70 molecule in the gas phas e, with angular analysis, has been investigated in the intermediate en ergy range (from excitation thresholds up to 80 eV above threshold). T he occurrence of a 'plasmon like' process, different from the one-elec tron dipole-allowed excitations, has been detected based on a differen t angular behaviour. Optically forbidden transitions appear only weakl y and are observed at 1.9 and 4.8 eV. In contrast to the case of C-60, a small vibrational excitation, possibly resonant in character, has b een observed around 2 eV incident energy. Variations in the cross sect ions and angular behaviour of the main excitation processes observed a re presented.