Ionization of hydrogen molecular ions by antiproton impacts

Abstract

Ionization cross sections in collisions of antiprotons $(\overline{p})$ with $\mathrm{H}_{2}{}^{+}$ molecules are calculated for incident energies in the range of $2--500\phantom{\rule{0.3em}{0ex}}\mathrm{keV}$ by using a semiclassical impact-parameter method. The electronic motion is solved in a numerically accurate manner by means of a discrete variable representation. A sudden approximation is applied to the description of the molecular rotation and vibration. The present $\overline{p}+\mathrm{H}_{2}{}^{+}$ ionization cross sections are compared with the theoretical results of the ionization in $\overline{p}+{\mathrm{He}}^{+}$ and the experimental results of the production of ${\mathrm{H}}^{+}$ ions in $\overline{p}+{\mathrm{H}}_{2}$.