Charge Transfer In Collisions Between Diatomic Molecular Ions And Atomic Hydrogen Using Merged Beams (Vol 84, 062716, 2011)

A merged-beam technique is used to measure charge transfer (CT) cross sections for the (O-2(+), D) and (CO+, D) systems over a wide range of collision energy from 20 eV/u to 2 keV/u. At the higher energies where the collision is rovibrationally frozen and the differences in the Q values of the CT process can be neglected, the cross sections all converge to (7.5 +/- 0.5) x 10(-16) cm(2) at 2 keV/u and are consistent with a rovibrational frozen (H-2(+), H) calculation. Toward lower velocities, (O-2(+), D) and (CO+, D) have consistently similar cross sections but diverge below 60 eV/u. In contrast, previously reported merged-beam measurements for (D-2(+), H), a system with fewer electrons on the molecular core, no electronic excited states, and relatively fewer charge transfer channels, shows a decreasing cross section toward lower energies. These different trends are compared to previous merged-beam measurements of charge transfer with H for several atomic 4+ ions (Si4+, Ne4+, N4+, and C4+) which have a variety of electrons on the core.