Absolute Measurement of the Total Cross Section in 2 keV/u - 10 keV/u D2+ + H Charge Transfer Collisions.

The ion-atom merged-beam apparatus at Oak Ridge National Laboratory in Oak Ridge, Tennessee has been successful in measuring absolute cross sections of charge transfer between atomic ions and hydrogen atoms for many years. Moreover, the first molecular ion measurements with the current version of the apparatus, performed for D₂⁺ + H, are used to benchmark theory between 0.5 - 2 keV/u including vibrationally specific adiabatic theory for the (H₂–H)⁺ complex, the most fundamental ion-molecule two-electron system. The absolute cross section of direct charge transfer in D₂⁺ + H was measured with the merged-beam apparatus between 2.0 keV/u - 10 keV/u, and is presented here. The new measurements agree with McGrath et al. measurements at their lowest energy of 10 keV/u. These new measurements show that, besides the local maximum at 0.1 keV/u observed in our previous measurements, the absolute cross section also has a maximum around 2.2 keV/u, delineating an oscillation-like structure. [ABSTRACT FROM AUTHOR]