Conversion of Ion Types in Nitrogen

Abstract

A single-shutter drift tube, together with a hot-filament-type ion source, was used to investigate the conversion and drift properties of ions in nitrogen. Three different species of ions, namely N+, N2+, and N3+, were detected, and their drift velocities in nitrogen were measured over a range of E/p0 (ratio of electric field strength to pressure) from 10 to 200 V/(cm·mm Hg). N2+ was found to undergo time-rate-controlled conversion to N3+. Theoretical solutions of such a drift transient have been obtained and were compared with experiment. The attachment frequency α was deduced from the transient form, and its dependence on pressure and E/p0 measured. It was found that α∝p02 exp[A (−E/p0) ].