Multiple-ionization and dissociation dynamics of a rare gas dimer induced by highly charged ion impact

Abstract

Low-energy collision experiments of an argon dimer with Ar9+ were performed to measure branching ratios and kinetic energy release (KER) distributions for multiply ionized dimers. Two well-separated KER peaks are observed at 3.8 and 5.3 eV for the doubly ionized dimers, and are assigned to direct Coulombic dissociation and radiative electron capture followed by ionic dissociation, respectively. For the dissociation channels Ar2++Ar+, Ar3++Ar+ and Ar2++Ar2+, the KER distributions show a single peak, the positions of which agree well with those expected for Coulombic dissociation. The branching ratio of asymmetric charge sharing, Ar3++Ar+, is larger than that of symmetric charge sharing, Ar2++Ar2+. These results represent unambiguous evidence of a strong limitation of charge mobility across the Ar dimer.