The Dissociation of Benzene (C6H6), Pyridine (C5H5N) and Cyclohexane (C6H12) by Electron Impact

Abstract

The dissociation of ${\mathrm{C}}_6$ ${\mathrm{H}}_6$, ${\mathrm{C}}_5$ ${\mathrm{H}}_5$N, and ${\mathrm{C}}_6$ ${\mathrm{H}}_{12}$ by electron impact has been investigated with a mass spectrograph. Four doubly charged and thirty-one singly charged positive ions were observed in the dissociation of benzene. The relative abundance, for electrons of 72 volts energy, and the appearance potential are given for each ion. The first and second ionization potentials of benzene are 9.8±0.1 and 17.2±1.0 volts, respectively. The ionization potential of ${\mathrm{C}}_5$ ${\mathrm{H}}_5$N is 9.8±0.2 volt and of ${\mathrm{C}}_6$ ${\mathrm{H}}_{12}$, 11.0±0.2 volt. In each of the three vapors, certain of the ions resulting from the dissociation process have a doublet character. The components have a constant energy separation independent of magnetic field. The components also have different appearance potentials. The interpretation given is that these particular ions are formed by two different processes, one of which imparts a definite amount of kinetic energy to the ion.