Monte Carlo simulation studies of diffusion coefficients and mobilities for Rb+–N2 with anisotropic model potential and comparison with experimental measurements

Abstract

Monte Carlo simulation calculations were made of the mobility, and the transverse and longitudinal diffusion coefficients of Rb ϩ swarms drifting in nitrogen gas using an anisotropic model potential, which is constructed by extending the Tang-Toennies model to the alkali ion-diatomic molecule system. The potential parameters have been obtained from the combining rule and some published data. Scattering data for the collision of Rb ϩ with N 2 molecule, which are indispensable to the simulation procedure, are obtained by infinite order sudden approximation. Detailed comparison between the simulated results and recent measurements of transverse diffusion as well as previously published mobility and longitudinal diffusion data suggests that the present interaction potential may represent reasonably well the true interaction in the long and intermediate ranges. In addition, it also was found that previous experimental results of longitudinal diffusion and reduced mobility in the high E/N region were possibly too high due to systematic errors. © 1997 American Institute of Physics. ͓S0021-9606͑97͒50504-6͔