Reactive collisions of atomic antihydrogen with the H2 and H2+ molecules

The fermion molecular dynamics (FMD) method is used to determine the protonium (Pn) formation and total destruction cross sections for collisions of antihydrogen(H-bar) with the H2 molecule and the H2+ molecular ion at collision energies above 0.1 au in the centre-of-mass system. The cross sections and initial quantum numbers are compared with the analogous cross sections for H-bar+H, p-bar+H, p-bar+H2 and p-bar+H2+ previously calculated. Like the p-bar projectile, the protonium-formation cross sections for the H-bar projectile are much larger and extend to higher energies with the molecular targets than with the atomic target. The possibility is considered that a relatively long-lived state of the H-barH molecule may be formed in rearrangement scattering of H-bar+H2 at low energies