Theoretical study of mutual neutralization inHe++H−collisions

Abstract

Total and differential cross sections for mutual neutralization in ${\mathrm{He}}^{+}$ and ${\mathrm{H}}^{\ensuremath{-}}$ collisions at low to intermediate (0.001 eV to 100 eV) are calculated ab initio and fully quantum mechanically. Atomic final-state distributions and isotope effects are investigated. The theoretical model includes dynamics on eleven coupled states of $^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ symmetry, where autoionization is incorporated. The potential-energy curves, autoionization widths, and nonadiabatic couplings of electronic resonant states of HeH are computed by combining structure calculations with electron scattering calculations. The nuclear dynamics is studied using a strict diabatic representation of the resonant states. Effects of rotational couplings between $^{2}\mathrm{\ensuremath{\Sigma}}^{+}$ and $^{2}\mathrm{\ensuremath{\Pi}}$ electronic states are investigated in the pure precession approximation.