Crossed-Beam Experiment for the Scattering of Low Energy Electrons from Gas Phase C₆₀

Abstract

Elastic electron scattering spectra of C₆₀ in the vapor phase were recorded from 1 to 11.5, eV and scattering angles from 30° to 90°. Electron energy loss spectra are given for a loss from 1 to 55, eV at impact energies of 50 and 100, eV (5°). They confirm the known optically allowed transitions and resolve the ≈ 6, eV π -electron plasmon-peak at least into four steps at 5.8, 6.1, 6.3, and 6.5, eV. A small peak of width 2, eV has been found at 28.3, eV, the position of the “σ +π -plasmon” in solid films. Vibrational excitations were recorded at 7, eV for angles from 20° to 60° with a resolution of 34, meV and show two peaks at 0.06 to 0.11, eV and at 0.15 to 0.20, eV both of which contain optically forbidden transitions. The elastic DCS at 7, eV and a scattering angle of 30° is estimated to be of order 5× 10^-14, cm²/sr.