Experimental transverse diffusion and Monte Carlo simulation studies of Rb+ swarm drifting in He gas

Abstract

Experimental measurements have been made of the transverse diffusion of Rb+ swarms drifting in He gas at E/N (drift field to gas concentration ratio) values ranging from 5 to 500 Td, and at gas temperatures between 302 and 304 K. Results with typical errors of ±3% are reported. In addition, Monte Carlo simulation (MCS) calculations were made of the mobility, transverse, and longitudinal diffusion coefficients of Rb+ in He using two recently proposed interaction potentials. Comparisons of the MCS results with available experimental data give an indication of the validity and accuracy of the respective assumed interaction potentials at different interatomic distances. Further calculations of the transverse and longitudinal diffusion coefficients from known mobility values using the generalized Einstein relations based on the three-temperature theory suggest that the theory is fairly accurate at all E/N values despite the high ion-neutral mass ratio. © 1995 American Institute of Physics.