Coulomb explosion and binary encounter processes in collisions between slow ions and small molecules of biological interest

Abstract : In this work we study the ion impact induced fragmentation of small molecules, which are relevant for radiation damage studies in biological tissues. We present double differential ion emission yields for collisions of N6+ ions with water and methane molecules at 15 and 30 keV impact energies. The angular distribution of the fragment ions shows post-collision and nucleus-nucleus binary collision effects. In the multiple capture energy range, a strong interplay is indicated between the Coulomb explosion and the binary collision mechanisms. In the energy region, where triple capture is dominant, an unexpected angular distribution was found for water fragments, which may be attributed to orientation sensitivity of some of the capture channels. Such processes are relevant for astrophysics and radiation therapy.