Transport Coefficients of Ar⁺, Ne⁺ and N₂⁺ Ions in CH₄

Abstract

The drift and longitudinal diffusion of N₂⁺, Ar⁺ and Ne⁺ in CH₄ has been studied with a drift-tube mass spectrometer. Values of the reduced mobility and of the density-normalized longitudinal diffusion coefficient of these ions are reported over a range of E/N from 50 to 300 Td. Gaseous ion mobilities are mainly dependent on ion-neutral collision energies and it can be directly related to ion-neutral interaction potentials. We estimated the ion-neutral interaction potentials of these ions and CH₄ from the experimental results.