State selective capture cross sections in slow collisions of fully and partially stripped ions with the molecular hydrogen: A progress report

Single-electron capture cross sections from H-2 by a number of fully and pa rtially stripped ions (2 less than or equal to q less than or equal to 6) h as been calculated using a semi-classical Molecular Orbital approximation. During the course of the collision a transient quasi-molecule comprising th e entrance and various exit channels of the charge-transfer reactions is co nsidered. Freezing the molecular details of the target, the effective bindi ng of the active electron inside the transient molecule is simulated employ ing pseudo-potential. A multi-channel calculation is carried out in which t he number of molecular states to be coupled together is decided by the coll ision dynamics of the individual pair. The calculated cross sections agree very well with the available experimental results. Although the Landau-Zene r mechanism is mainly responsible for the observed state-selective charge-e xchange process, no generalization in terms of projectile charge or structu re is possible to predict the behavior of individual interactions. The tota l cross sections, along with their l-distribution, for the O6+-H-2 system a re reported here for the first time. (C) 1999 Elsevier Science B.V. All rig hts reserved.