Low-energy electron-impact dissociative excitation of molecular hydrogen and its isotopologues

Abstract

We apply the adiabatic nuclei convergent close-coupling method to electron-impact dissociative excitation of ${\mathrm{H}}_{2}$ in the low-energy regime. Differential and integrated cross sections are presented for excitation of the $b^{3}\mathrm{\ensuremath{\Sigma}}_{u}^{+}$ state, the primary pathway to dissociation of ${\mathrm{H}}_{2}$ at low energies. Agreement with experiment is satisfactory. Results are also presented for the isotopologues ${\mathrm{D}}_{2}$, ${\mathrm{T}}_{2}$, HD, HT, and DT, which show a pronounced isotope effect near threshold in both the differential and integrated cross sections.