OBSERVATION OF INTERFERENCE IN CHARGE-EXCHANGE SCATTERING IN HE2++HE+COLLISIONS

We report the first observation of interference in charge exchange col lisions between two ions. Employing the crossed-beams technique in con junction with signal recovery methods, angular differential cross sect ions have been measured for charge transfer in He2+ + He+ collisions a t barycentric energies between 0.5 and 10.2 keV. The oscillatory struc ture observed is in agreement with quantum calculations and can be int erpreted in terms of interference between scattering into gerade and u ngerade molecular states, which arise due to the identity of the nucle ar charges.