Orientation dependence of multiple electron transfer in collisions of slow highly charged ions with rare gas dimers

We investigate the orientation dependence for multiple electron transfer in collisions of slow highly charged ions with rare gas dimers. For this purpose, we modify the previous three-center Coulombic over-barrier model for the target of covalent bonding molecules, so as to take full account of three-center nature in electron dynamics during a collision. The model developed is applied to the collisions of A(8+) + Ne-2, where charge state distributions are derived for Coulomb explosion fragments. The distributions are predicted to be qualitatively different for parallel and perpendicular molecular orientations with respect to the ion beam; fragment ion pairs with symmetric charges are dominant when parallel, while asymmetric charges when perpendicular. This result is in sharp contrast to that for covalent molecules, reflecting electron localization at atomic centers in rare gas dimers. (C) 2002 Elsevier Science B.V. All rights reserved.