Two-center interference in fast proton–H2-electron transfer and excitation processes

We present experimental evidence for a strong dependence on the angle between the molecular axis of H2 and the direction of the incoming projectile (p) in the cross section for transfer excitation in fast p−H2 collisions. For collision energies of 1.0 and 1.3MeV we find good agreement between the observed data and an analytical expression based on a two-atomic-center description using Brinkman-Kramers amplitudes. This clearly shows that the observed angular dependence is a result of quantum mechanical interference and not a trivial geometrical effect.