Elastic Scattering, Diffusion, and Excitation Transfer of Metastable Helium in Helium

Abstract

The dynamics of the resonance collision of metastable and normal helium atoms has been examined and calculations have been performed for elastic scattering, diffusion, and excitation transfer. To facilitate this analysis, accurate ab initio calculations of the pertinent interaction potentials have been carried out. The use of these more accurate potential curves in the framework of the original dynamical formulation of the collision process by Buckingham and Dalgarno leads to serious discrepancies between calculations and experiment for the elastic scattering cross section and the coefficient of diffusion. The rate constant for the excitation transfer reaction, however, is in reasonable agreement with experiment, over a wide range of temperatures.