Electronic excitation of C70 in the gas phase by electron energy loss spectroscopy

Electron energy loss spectroscopy of the C70 molecule in the gas phase, with angular analysis, has been investigated in the intermediate energy range (from excitation thresholds up to 80 eV above threshold). The occurrence of a ‘plasmon like’ process, different from the one-electron dipole-allowed excitations, has been detected based on a different angular behaviour. Optically forbidden transitions appear only weakly and are observed at 1.9 and 4.8 eV. In contrast to the case of C60, a small vibrational excitation, possibly resonant in character, has been observed around 2 eV incident energy. Variations in the cross sections and angular behaviour of the main excitation processes observed are presented.