Electron emission from proton-hydrocarbon-molecule collisions at 0.3-2.0 MeV

Cross sections, differential in ejection energy and angle, for electron emission from methane, ethane, ethylene, acetylene, and benzene molecules following proton impact have been measured for protons of 0.3-, 1.0-, and 2.0-MeV energy, in an attempt to observe a variation in the electron yield attributable to the chemical form or molecular binding of the target atoms. The results indicate that emission cross sections for electrons ejected with energy greater than about 10 eV show no effects related to the molecular structure within this group of molecules. When the results are compared with similar data for molecular hydrogen however, one observes a significant difference in the angular dependence of the emission cross sections between the hydrocarbons as a group and hydrogen; the emission from the hydrocarbons is more isotropic than from hydrogen. This observation indicates that the amount of ionization produced by energetic charged particles may be different in different gaseous mixtures containing hydrogen and hydrocarbon gases. The double-differential cross sections for the group of hydrocarbons are found to be scalable in terms of the number of weakly bound electrons in the molecule.