DIFFRACTION IN THE BINARY ENCOUNTER ELECTRON PEAK OBSERVED IN COLLISIONS OF 0.6 MEV AMU-1 I7+, I23+ AND AU11+ PROJECTILES WITH HE AND AR

Relative double differential cross sections for electron emission from collisions of 0.6 MeV amu-1 I7+ and I23+ projectiles with Ar and Au11+ projectiles with He were measured for electron energies from 100 eV to 2000 eV and for angles from 0-degrees to 50-degrees. Experimentally observed sudden shifts of the position of the binary encounter peak were interpreted as resulting from quantum interference in the scattering of target electrons from the partially stripped projectile ion. To this end calculations for the elastic scattering of free electrons initially at rest in the laboratory reference frame from the screened projectile field as well as model calculations of binary encounter electron production taking into account the target Compton profile were performed and compared with the experimental results. Good agreement was obtained for the angular locations of these shifts as well as for the angular distribution of the binary encounter electron yield.