Alignment effects in electron capture from D₂⁺ molecular ions by doubly charged projectiles

I. Reiser¹, H. Bräuning², C. L. Cocke¹

1) JR MacDonald Laboratory, Kansas State University, Manhattan, KS, USA
2) Institut für Kernphysik, Strahlenzentrum, Justus-Liebig University, Giessen, Germany

D₂⁺ We have experimentally determined the alignment dependence of the electron capture cross section in collisions between D₂⁺ and Ar₂⁺ (v_coll = 0.19 a.u.), N₂⁺ (v_coll = 0.23 a.u.) and He₂⁺ (v_coll = 0.4 a.u. and v_coll = 0.5 a.u.). The experiment was carried out at the KSU ion-ion collision facility, where two ion beams intersect each other at 90°. Positions and flight times of both molecular fragments are measured using a multi-hit detector system. True ion-ion collision events are identified through detecting the two D⁺ ions from the breakup and the charge-changed projectile in a triple coincidence. The alignment of the molecular ion in the collision is determined by measuring the internuclear vector of the two fragments after the electron is removed by the projectile. Pronounced alignment dependence is observed, favoring capture when the molecular ion is perpendicular to the relative velocity, for all systems. The data is compared to predictions of an interference model for charge transfer in ion-molecule collisions.

This work was supported by the Chemical Sciences, Geosciences and Biosciences Division,
Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy.

Submitted to DAMOP 2002, May 2002 in Williamsburg, VA.

 

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