Dynamic Coupling Phenomena in Molecular Excited States. III. Associative Ionization and Dissociative Recombination inH2

A detailed calculation based on a perturbed stationary-state description is presented for associative ionization of hydrogen atoms. Specific rate constants $k_{\mathrm{AI}} \mathrm{}(v,K,T)\mathrm{}$ are evaluated for the set of electronic states correlating with $\mathrm{H}\mathrm{}(n=1\mathrm{})+\mathrm{H}\mathrm{}(n=3\mathrm{})\mathrm{}$ for associative ionization into vibrational ($v=0-8\mathrm{}$) and rotational ($K=0-21\mathrm{}$) states of $\mathrm{H}_2^{}{}_{}{}^{+}\left(X^2{\Sigma }_g^{+}\right)$ at $T=300\mathrm{}$ °K and at $T=600\mathrm{}$ °K. Cross sections $Q_{\mathrm{AI}}\mathrm{}(v,K,E)\mathrm{}$ are given for the most significant electronic state, the ($1s\sigma ,4s\sigma$) united atom configuration, and, by microscopic reversibility, cross sections for the reverse reaction, dissociative recombination, are obtained. Cross sections for associative ionization at thermal energies, $Q_{\mathrm{AI}}(v,K,{10}^{-3\mathrm{}}\mathrm{a}.\mathrm{u}.\mathrm{})$, are at most of a magnitude about ${10}^{-18\mathrm{}}$ ${\mathrm{cm}}^2$. Corresponding specific rate constants, $k_{\mathrm{AI}}$ ($v,K,300\mathrm{}$ °K), fall in the range ${10}^{-14\mathrm{}}$-${10}^{-13\mathrm{}}$ ${\mathrm{cm}}^3$/sec and display a temperature dependence $k_{\mathrm{AI}}\mathrm{}\left(T\right)\mathrm{}\propto T^{-0.33\mathrm{}}$. Dissociative recombination cross sections, $Q_{\mathrm{DR}}(v,K,{10}^{-3\mathrm{}}\mathrm{a}.\mathrm{u}.\mathrm{})$, are obtained for the $v=4-8\mathrm{}$ vibrational states, with magnitudes about ${10}^{-16\mathrm{}}$ ${\mathrm{cm}}^2$. The resulting specific rate constants, $k_{\mathrm{Dr}}$ ($v,K,300\mathrm{}$ °K), are at most