Rotational excitation of CH4by low-energy-electron collisions

Abstract

Cross sections for the rotational excitation in vibrationally elastic e-+CH4 collisions have been measured for the impact energies 0.5, 5, 7.5 and 10 eV. Absolute state-to-state cross sections have been determined from the broadened energy loss peaks by using an analysis of Shimamura (1983). The results are compared with calculations of Jain and Thompson (1983) and of Abusalbi et al (1983). In the resonance region the cross sections for pure rotational excitation are larger than Jain and Thompson predicted, whereas their relative angular dependences-especially for the impact energy 5 eV-seem to follow the experimental curves. At 0.5 eV only weak rotational excitation occurs, and the experimental and theoretical cross sections are in agreement within experimental error.