Excitation of Hydrogen Molecule by Electron Impact. III. Singlet-Triplet Excitations

Abstract

One-center wave functions of Huzinaga along with the Ochkur approximation have been employed to investigate the exchange excitation of the hydrogen molecule by electron impact from the ground electronic state $X\left(1s\sigma {{}_{}{}^1{}_{}{}^{}\Sigma _g^{}{}_{}{}^{}}^{+}\right)$ to the triplet $a\left(2s\sigma {{}_{}{}^3{}_{}{}^{}\Sigma _g^{}{}_{}{}^{}}^{+}\right)$, $b\left(2p\sigma {{}_{}{}^3{}_{}{}^{}\Sigma _u^{}{}_{}{}^{}}^{+}\right)$, and $c\left(2p\pi {}_{}{}^3{}_{}{}^{}\Pi _u^{}{}_{}{}^{}\right)$ electronic states. Since the lowest triplet state $b\left({{}_{}{}^3{}_{}{}^{}\Sigma _u^{}{}_{}{}^{}}^{+}\right)$ is a repulsive state and the intercombination of the triplet and the singlet states are optically forbidden, the singlet-triplet excitations give rise to the dissociation of the hydrogen molecule into two hydrogen atoms. The shape of the theoretical curve for the dissociation cross section is in general accord with the experimental data of Corrigan. Theoretical efficiencies of the dissociation of the hydrogen molecule by electron impact and of the emission of the continuous radiation due to $a\left({{}_{}{}^3{}_{}{}^{}\Sigma _g^{}{}_{}{}^{}}^{+}\right)\to b\left({{}_{}{}^3{}_{}{}^{}\Sigma _u^{}{}_{}{}^{}}^{+}\right)$ transitions have also been computed and are compared with the available experimental data.