State-selective charge transfer in slow collisions of partially stripped He-like ions withH2

Abstract

State-selective charge transfer from ${\mathrm{H}}_{2}$ by ${\mathrm{C}}^{4+}$ and ${\mathrm{N}}^{5+}$ in the low-energy region $(0.01<~E<~2{\mathrm{keV}\mathrm{}\mathrm{amu}}^{\mathrm{\ensuremath{-}}1})$ has been investigated employing the semiclassical, impact parameter, close-coupling method based on a molecular expansion augmented with the plane-wave translation factor. Freezing the molecular features of the target, the colliding system is approximated by a pseudo-one-electron entity. The method of pseudopotential is applied to account for the binding of the electron in the transient diatomic quasimolecule. A large number of close-coupled equations are solved to obtain probabilities of transitions, and thereby evaluate the partial capture cross sections. Both the total and partial capture cross sections agree well with the recent experimental results. The low-energy behavior of the total cross sections due to ${\mathrm{C}}^{4+}$ and ${\mathrm{N}}^{5+}$ is very different owing to their different core structure, albeit both are He-like ions; the former shows some fluctuations whereas the latter registers a monotonic rise with E. The possible role of the projectile core size on the final l distribution of the estimated cross section is discussed. The inclusion of the rotational couplings is essential for the correct low-energy behavior of the cross sections. For ${\mathrm{N}}^{5+}{+\mathrm{H}}_{2},$ the low-energy l distribution of the capture cross sections has been presented.