Ionization of Nitrogen Molecules by Nitrogen Molecules

Abstract

The ionization cross section for ${\mathrm{N}}_2$ molecules on impact with ${\mathrm{N}}_2$ molecules has been measured over the laboratory energy range from 30 to 1000 ev. The incident molecular beam was produced by the technique of ionization by electron impact, electrostatic acceleration and neutralization by charge transfer. The measurements were carried out in a low-pressure parallel plate ionization chamber. Particular attention was paid to the problem of secondary electrons. Ionization was observed a few volts above threshold. Cross sections which were obtained ranged from ${10}^{-20\mathrm{}}$ to ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$. The curve of cross section vs incident particle energy showed structure indicative of competing processes.