The Efficiencies of Ionization and Ionization Potentials of Various Gases Under Electron Impact

Abstract

The efficiencies of ionization of ${\mathrm{N}}_{2}$, CO, ${\mathrm{O}}_{2}$, NO, ${\mathrm{H}}_{2}$ and ${\mathrm{C}}_{2}$${\mathrm{H}}_{2}$ by electron impact have been measured. The curves are similar to those of He, Ne, A and Hg vapor. The ionization potentials of the molecules were found to be: ${\mathrm{N}}_{2}$, 15.7; CO, 14.1; ${\mathrm{O}}_{2}$, 12.5 and 16.1; NO, 9.5; ${\mathrm{H}}_{2}$, 15.6; and ${\mathrm{C}}_{2}$${\mathrm{H}}_{2}$, 11.6. The probable error in each case is about a tenth of a volt. Negative ions were formed by electron impact in NO, CO, ${\mathrm{O}}_{2}$ and ${\mathrm{C}}_{2}$${\mathrm{H}}_{2}$. None were observed in ${\mathrm{H}}_{2}$ or ${\mathrm{N}}_{2}$.