Antiproton-impact ionization of H2

Ionization processes in antiproton collisions with H₂ are studied by direct solution of the time-dependent Schrödinger equation. A time-dependent close-coupling method based on an expansion of a one-electron 3D wavefunction in the field of H⁺₂ is used to calculate single-ionization cross sections at incident energies ranging from 50 keV to 1.5 MeV. Averaging over the molecular orientations, the single-ionization cross sections are in reasonable agreement with time-dependent basis set calculations and experiment. A time-dependent close-coupling method based on an expansion of a two-electron 6D wavefunction in the field of H^{2 +}₂ is used to calculate single- and double-ionization cross sections at an incident energy of 100 keV. Initiatory 6D results for the H⁺₂ production cross section range are somewhat lower than experiment, while the H⁺ production cross section range brackets experiment.