Radiative Charge Transfer between Metastable Helium and Lithium Cations

Abstract

Abstract Depopulation of long-lived metastable helium He(23S) by spontaneous radiative charge transfer in collisions with lithium cations Li+ is investigated using a fully quantal approach. The corresponding transitions start in continuum states of the initial electronic state b 3Σ+ and end in continuum states of the final electronic state a 3Σ+. The process is characterized by cross sections and rate coefficients, which are calculated as functions of initial collision energy and temperature, respectively. Particular consideration is paid to the proper description of the high-energy cross sections in order to include their contributions to the total rate coefficient at high temperatures, where its asymptotic behavior is analyzed. The calculated total rate coefficients are in the range 1.75 × 10−15 – 3.16 × 10−14 cm3 s−1. The comparison with other relevant depopulation mechanisms shows that the radiative processes prevail for temperatures below 3000 K, while at higher temperatures the nonradiative inelastic processes are dominant.