Electron impact dissociative ionization of ethane: Cross sections, appearance potentials, and dissociation pathways

摘要

Cross sections of the electron impact ionization as well as the dissociative ionizations of ethane have been measured for electron energies from threshold to 600 eV. The complete collection of all the ionic fragments has been verified directly in the experiment. The results are thus believed to be reliable. The results for the products of H-n(+)(n = 1-3) are obtained for the first time. The appearance potentials of the ionic products are also measured. The disagreement with respect to the appearance potentials between the present work and previous measurements is explained by the dipole-forbidden transitions in the electron impact excitation process. The starting channels for the ionic products are discussed based on the appearance potentials, the kinetic energy distributions of the ionic products, and the ejection of the electrons out of the different orbitals of the ethane molecule. (C) 1998 American Institute of Physics. [References: 27]