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 partially stripped ions (2 less than or equal to q less than or equal to 6) has been calculated using a semi-classical Molecular Orbital approximation. During the course of the collision a transient quasi-molecule comprising the entrance and various exit channels of the charge-transfer reactions is considered. Freezing the molecular details of the target, the effective binding of the active electron inside the transient molecule is simulated employing pseudo-potential. A multi-channel calculation is carried out in which the number of molecular states to be coupled together is decided by the collision dynamics of the individual pair. The calculated cross sections agree very well with the available experimental results. Although the Landau-Zener mechanism is mainly responsible for the observed state-selective charge-exchange process, no generalization in terms of projectile charge or structure is possible to predict the behavior of individual interactions. The total cross sections, along with their l-distribution, for the O6+-H-2 system are reported here for the first time. (C) 1999 Elsevier Science B.V. All rights reserved.