Population of Rydberg states by electron capture in fast-ion–atom collisions

The l,m-substate distribution in low-lying Rydberg manifolds (n≊10) following electron capture ${\mathrm{H}}^{+}$+H(1s)→H(n)+${\mathrm{H}}^{+}$ is calculated at high velocities (v>1 a.u.) in the continuum-distorted-wave (CDW) approximation. The standard CDW approximation is modified to account for final-state Stark mixing of the Rydberg manifold in the exit channel using the post-collision-interaction model. The influence of multiple-scattering contributions is analyzed and comparison is made with ${\sigma }_{\mathrm{lm}}$ predicted by the Born approximation. We find that the double-scattering contribution, closely connected with the classical Thomas process, becomes visible in the CDW approximation at surprisingly low nonasymptotic velocities.