Dissociative Recombination in Helium Afterglows

Abstract

Helium-afterglow experiments which have been interpreted in the literature in terms of dissociative recombination of $\mathrm{He}_2^{}{}_{}{}^{+}$ cannot be so interpreted in light of recent experimental and theoretical developments. These include the quantitative theory of collisional-radiative recombination, estimates of $\mathrm{He}_2^{}{}_{}{}^{+}$ vibrational relaxation times, considerations of $\mathrm{He}_2^{}{}_{}{}^{*}$ (excited-state) potential curves, and rather detailed experimental results from steady-state flowing afterglow systems.