Evolution of a model ion explosion spike in potassium chloride by molecular dynamics

Department of Chemical Engineering and Chemical Technology Imperial College of Science, Technology and Medicine London, SW7 2BY, UK

Received: 18 February 2002
Accepted: 29 May 2002

Abstract

A swift ion passing through a crystal of containing 12800 ions generates by ionisation and Auger cascade a linear cluster of positively charged ions which expands by Coulomb repulsion (ion explosion). After rapid outward motion, collisions become chaotic causing radiation damage in a transient quasicrystalline lattice created by the intense electric field of the initial cluster. By 1 a cylinder of disordered material 78 in diameter is formed. This is stabilised by a random distribution of spike ions, but after appropriate charge neutralisation and annealing yields a central core of chlorine surrounded by a disordered zone of span 48, rich in anion vacancies. Save for the annealing observed in the present binary solid, these findings mimic phenomena found in high- superconductors, and include the notion of chemical decomposition.