Dissociative recombination in argon: Dependence of the total rate coefficient and excited-state production on electron temperature

Abstract

A three-mode microwave afterglow apparatus and high-speed grating spectrometer are used to study dissociative recombination in argon. The total rate coefficient may be represented by $\alpha \left[{\mathrm{Ar}}_2^{+}\right]=9.1\mathrm{}\times {10}^{-7\mathrm{}}\times {\left[\frac{300}{T_e\left(\mathrm{K}\right)}\right]}^{0.61}$ ${\mathrm{cm}}^3$/sec over the electron-temperature range $300\le T_e\le 8500$ K, with $T_{+}=T_{\mathrm{gas}}=300\mathrm{}$ K. The excited states produced by the dissociative recombination are determined at $T_e=300\mathrm{} \mathrm{and} 7200$ K. In both cases, the $4p$ and $4p^{\prime }$ states are found to be the most strongly populated.