Threshold peaks and structures in elastic and vibrationally inelastic electron impact cross sections for CS2

Elastic, vibrationally inelastic and superelastic cross sections were measured for electron impact on CS2 at 135 deg., with emphasis on the threshold region. The elastic cross section rises dramatically at low energies. The cross sections for the excitation of all three fundamental vibrations (010), (100) and (001) have very strong threshold peaks, more than ten times higher than those observed for CO2. The elastic and the (010) and (100) inelastic cross sections have deep narrow structures at energies up to about 0.3 eV. The structures are weak for the (001) vibration. Substantial excitation of overtone vibrations is observed even near threshold. The threshold structures appear to be caused primarily by the 2 Πu valence state of CS2-. Various broad resonant peaks are observed in the cross sections in the 1-12 eV range