Young-Type Interference in Collisions between Hydrogen Molecular Ions and Helium

The dissociative electron transfer from He into 10 keV H₂⁺ was measured in a kinematically complete experiment by using the cold target recoil ion momentum spectroscopy imaging technique in combination with a highly resolving molecular fragment imaging technique. The electron transfer into the dissociative b³Σ_u⁺ state of H₂ could be selected by kinematic conditions. We find a striking double slit interference pattern in the transverse momentum transfer which we can modify by selecting different internuclear distances. Compared to an optical double slit, interference minima and maxima are interchanged. The latter is the result of a phase shift in the electronic part of the wave function.