Electron emission in fast heavy ion impact ionization of C₆₀ and Ne: giant plasmon excitation

We have measured the energy and angle differential ejected electron spectra of C₆₀ as well as Ne atoms in collisions with 4 MeV/u bare fluorine projectile ions. Absolute cross sections have been estimated for electron emission in the energy range of 1 eV–300 eV, including the KLL-Auger electrons for various angles between 30° and 150°. The double differential cross sections for C₆₀ have been compared with the state-of-the-art CDW-EIS model under CNDO approximation as well as with the data for the Ne target. The C₆₀ spectra at all angles show a broad giant plasmon resonance in the low energy region, which is not present in the atomic target data. The angular distribution reveals the dipolar nature of the plasmon excitation. The C K-LL Auger emission from C₆₀ reveals a large angular anisotropy compared to that for a hydrocarbon, e.g. methane target.