Calculation of Drift Velocities and Diffusion Coefficients for Xe$^+$ Ions in Gaseous Xe/$^3$He Mixtures

The drift velocities and the longitudinal and transverse diffusion coefficients for Xe
⁺
ions in gaseous Xe/
³
He mixtures, at atmospheric pressures, for Xe concentrations between 1 and 30%, and reduced electric field strengths, from about 3 to 70 Td, corresponding to E/p, from about 1 to 22.5 V cm
^-1
Torr
^-1
at 300 K, are calculated by simulation using a detailed Monte Carlo computer programme. This programme uses a set of integral and differential elastic collision cross sections for Xe ions with neutral He and Xe atoms, previously calculated by the authors using a modified Tang-Toennies ion-atom interaction potential and the JWKB approximation to calculate the phase shifts. The calculated drift velocities of Xe
⁺
ions depend strongly on the concentration of Xe in the mixtures.