Signature of Single Binary Encounter in Intermediate Energy He2+—Ar Collisions**Supported by the National Basic Research Program of China under Grant No 2010CB832902, the National Natural Science Foundation of China under Grants Nos U1332128 and 11274317, 10979007 and 11004202, and the Program of One Hundred Talents of the Chinese Academy of Sciences.

Abstract

We experimentally observe the signature of electron emission resulting from a single binary encounter mechanism in the intermediate collision energy regime of 30 keV/u He2+ on argon. Electron emission spectra in the transfer ionization are obtained and compared with classical calculations from a two-step model considering the initial electron velocity and re-scattering of the binary encounter electron in the recoil potential. Although the present reaction is actually a four-body problem, the model starting from a binary encounter gives out surprisingly good agreement with the experimental data. Our studies show that orbital velocities of the electron affect the emission patterns of ionized electrons significantly.