Light Emission in the VUV by Dissociative Excitation of CH4 with Low-Energy Electrons

Abstract

By bombardment of methane with low-energy electrons (0 - 400 eV) the molecule is dissociated in a single collision into excited C and H atoms or into excited H atoms and a free radical. The excited atoms emit a radiation in the vuv (900 Å -1700 Å). The appearance potentials and excitation functions are measured. Approximate values of the cross sections are given. The excitation cross section for the CII-Lines are extremely small (σ ≦ 10-21 cm2), whereas those for the H and CI-lines are of the order of 10-19-10-18 cm2 at 150 eV.