Ion-Ion Recombination Studies in Ambient Helium and Argon at Atmospheric Densities

摘要

The long history of theoretical studies of ion-ion recombination in gases has been reviewed extensively by Bates and by Flannery. In discussing the dependence of the recombination rate on gas density, one distinguishes different density regimes. In the zero-density limit, recombination occurs by two-body collisions only. Transfer of an electron at avoided potential curve crossings (Landau-Zener mechanism), perhaps accompanied by transfer of heavy particles, provides the neutralization mechanism. This process has been studied by beam experiments. At nonzero gas densities, collisional transfer of kinetic energy from the ion pair to the gas atoms provides an additional stabilization mechanism. The recombination rate increase with increasing density in this range the (Thomson regime) until it becomes limited by the rate at which ions drift or diffuse together (the Langevin-Harper regime). Reprints. (jes)