Dissociative electron capture and target ionization in 20 keV H2+ + Arcollisions: observation of an anisotropic fragment distribution

Abstract

Dissociative electron capture accompanied by target ionization(DECI) was studied for collisions of 20 keV H2+with Ar. A three-dimensional fragment imaging technique in combination with arecoil-ion time-of-flight method was used to measure the kinetic-energy releaseand the dissociation angle of the H–H fragment pair arising from the DECIprocess. We observed that the distribution of the dissociation angle is stronglyanisotropic. A three-body simulation suggests that collisions between theindividual fragments and the target significantly influence the two-bodydissociation of the H–H pair at impact parameters where the DECI processoccurs.