Studies of Ion—Neutral Reactions by a Photoionization Mass-Spectrometer Technique. I

Abstract

The use of a photoionization mass spectrometer for ion—molecule reaction studies is described. Ion‐source pressures up to 200 μ are employed, measured directly with a McLeod gauge. A method is described for determining ion residence times in the ion source at constant repeller field, using a pulsed‐light source. Drift velocities, diffusion coefficients, and ion temperatures are given for N₂⁺ ions in air as derived from an analysis of ion pulse shapes. Reaction studies are reported for nitrogen ions in air and nitrogen, and for hydrogen ions in hydrogen. The associated rate constants are derived.