Anisotropic ion emission in the fragmentation of small molecules by highly charged ion impact

Abstract

In this work, we present double differential ion emission yields measured by the method of fragment ion spectroscopy for collisions of N6+ and O7+ ions with water and methane molecules at ∼30 keV impact energies. The angular distribution of the fragment ions shows expected post-collision and nucleus-nucleus binary collision effects with the indication of an interplay between Coulomb explosion and binary collision mechanisms. We have found significant differences in the fragmentation patterns of methane for the two projectiles, which may be a signature of strong, resonant capture channels. For triple capture, an unexpected angular distribution has been found for water, which may be attributed to orientation sensitivity of some of the capture channels. Such processes can be highly important for radiation therapy and astrophysics. © 2008 Elsevier B.V. All rights reserved.