The Dissociation of HCN, ${\mathrm{C}}_2$${\mathrm{H}}_2$, ${\mathrm{C}}_2$${\mathrm{N}}_2$ and ${\mathrm{C}}_2$${\mathrm{H}}_4$ by Electron Impact

The dissociation of HCN and ${\mathrm{C}}_2$ ${\mathrm{H}}_4$ by electron impact has been investigated. An analysis of the results for these two molecules together with an analysis of previously published results on the dissociation processes occurring in ${\mathrm{C}}_2$ ${\mathrm{H}}_2$ and ${\mathrm{C}}_2$ ${\mathrm{N}}_2$ is presented. It is possible to assign reasonable processes of formation to all the observed ions from a knowledge of their appearance potentials, the known ionization potentials of certain atoms and atomic aggregates and the energies of dissociation of the parent molecule into various configurations. By a comparison of the results obtained for these four molecules, upper limits are assigned to the ionization potentials of various fragments obtained as dissociation products of hydrocarbons.