Reexamination of the Li+-He interaction potential

Abstract

Using various recently proposed interaction potentials for the Li+-He system, elaborate calculations of the mobility, longitudinal, and transverse diffusion coefficients of Li+ swarms in helium have been made by high-speed Monte Carlo simulations (MCS's). In addition, the transverse diffusion coefficients for this ion-neutral-atom pair have been experimentally measured with total errors of ±3%. The close agreement of the present experimental results with those of Skullerud, Eide, and Stefansson [J. Phys. D 19, 197 (1986)] as well as the faithful MCS reproduction of all three transport coefficients using the interaction potential proposed by Larsen et al. [J. Phys. B 21, 2519 (1988)] over the entire range of E/N (electric field to neutral-particle number density ratio) studied not only provides confirmation of their transport coefficient values, but also lends strong support for their proposed interaction potential. In comparison, the more recent potentials of Ahlrichs et al. [J. Chem. Phys. 88, 6290 (1988)] and of Koutselos, Mason, and Viehland [J. Chem. Phys. 93, 7125 (1990)] did not reproduce the experimental data quite as well. As a benchmark the MCS calculations have also provided evidence of the accuracy of the Kramers-Moyal expansion method in calculating the transport coefficients. © 1992 The American Physical Society.