Role of the projectile core in slow ion-molecule collisions: a molecular-state close-coupled treatment

The semiclassical molecular orbital approximation modified by a proper electron translation factor has been employed to investigate the dynamics of the low-energy charge transfer between molecular hydrogen and a few stripped ions having charges 2 less than or equal to Z less than or equal to 5. Freezing the molecular details of the target the colliding system has been treated as a quasi-diatomic molecule using the pseudo-potential technique that accounts for the effective binding of the electron in the combined nuclear field. Close-coupled equations are solved to obtain both the total and partial capture cross sections. The calculated total cross sections show good agreement with the available experimental measurements; the reported l-distributions for Li3+ and N5+ are new. A relative comparison for single-electron transfer from H-2 by other ions considered reveals the possible role of the projectile core; in the low-energy region the increasing core size affects considerably both the e-distribution and the shape of the total capture cross sections. The projectile C4+ exhibits a distinctive role due to its finite core; the calculated total cross sections show oscillations in complete agreement with the experimental findings, The presence of a finite core enhanced the contribution to the lower L-value substate of the final channel in accordance with the role of the Stark effect; the state-selective capture cross sections depend strongly on the size of the projectile core.