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 elec tron translation factor has been employed to investigate the dynamics of th e 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. Free zing the molecular details of the target the colliding system has been trea ted 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 part ial capture cross sections. The calculated total cross sections show good a greement with the available experimental measurements; the reported l-distr ibutions for Li3+ and N5+ are new. A relative comparison for single-electro n transfer from H-2 by other ions considered reveals the possible role of t he projectile core; in the low-energy region the increasing core size affec ts considerably both the e-distribution and the shape of the total capture cross sections. The projectile C4+ exhibits a distinctive role due to its f inite core; the calculated total cross sections show oscillations in comple te agreement with the experimental findings, The presence of a finite core enhanced the contribution to the lower L-value substate of the final channe l in accordance with the role of the Stark effect; the state-selective capt ure cross sections depend strongly on the size of the projectile core.