Associative ionization in collisions of H++H− and H(1 Associative ionization in collisions of ${\mathrm{H}}^{+}+{\mathrm{H}}^{\ensuremath{-}}$ as well as $\mathrm{H}(1s)+\mathrm{H}(ns)$ with $n=2,3,4$ is studied theoretically. Relevant adiabatic potential curves and nonadiabatic couplings are calculated ab initio and the autoionization from the lowest electronic resonant states in the ${}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g/u}^{+}$ and ${}^{3}{\mathrm{\ensuremath{\Sigma}}}_{g/u}^{+}$ symmetries are considered. The cross sections are obtained by solving the coupled Schr\"odinger equation, including a complex potential matrix, in a strict diabatic representation. The importance of using a nonlocal description of autoionization is investigated. Associative ionization is also studied for different isotopes of hydrogen. Calculated cross sections are compared with results from measurements.

Associative ionization in collisions of ${\mathrm{H}}^{+}+{\mathrm{H}}^{\ensuremath{-}}$ as well as $\mathrm{H}(1s)+\mathrm{H}(ns)$ with $n=2,3,4$ is studied theoretically. Relevant adiabatic potential curves and nonadiabatic couplings are calculated ab initio and the autoionization from the lowest electronic resonant states in the ${}^{1}{\mathrm{\ensuremath{\Sigma}}}_{g/u}^{+}$ and ${}^{3}{\mathrm{\ensuremath{\Sigma}}}_{g/u}^{+}$ symmetries are considered. The cross sections are obtained by solving the coupled Schr\"odinger equation, including a complex potential matrix, in a strict diabatic representation. The importance of using a nonlocal description of autoionization is investigated. Associative ionization is also studied for different isotopes of hydrogen. Calculated cross sections are compared with results from measurements.