Binary peak electrons from partially-stripped-ion-atom collisions

Abstract

Binary peak electrons in ionizing collisions arise from a close interaction between the heavy-ion projectile and an electron initially bound to the target atom. In fact, energy and momentum conservation yield the result that the binary peak should be found near the ejected electron velocity υ e = 2 υ p cos θ, where υ p is the projectile velocity and θ is the scattering angle of the electron. Further, the conventional view of such collisions predicts that the magnitude of the binary peak should scale as the square of the projectile charge. However, recent experiments have indicated anomalous scaling of the binary peak magnitudes and positions in the case of partially-stripped-ion impact. Since the origin of this structure occurs in very close projectile-target-electron collisions, investigation of the binary peak provides a sensitive probe of the electronic structure of the projectile. In this paper, we review current measurements and calculations, and provide predictions of binary peak magnitudes for the Xe q+ +H 2 system (1 ≤ q ≤ 54). We suggest that quantum interference effects in the elastic scattering of target electrons by the projectile play an important role in the formation of binary peaks for collisions by heavy, partially-stripped projectile ions.