Theory of electron capture by partly stripped ions in slow collisions with atomic hydrogen

The electron capture process X q+ -H to X (q-1)+ -H + is considered at intermediate-low velocities in a simple atomic collision model with quantum-defect wavefunctions for the final states of the captured electron. Electron translation factors are included in a consistent first-order approximation which allows a factorisation of the trajectory parameters in the coupling matrix. Close-coupling results are presented for a sequence of incident ions in charge state q=6. The results depend strongly on the configuration of core electrons. This effect is explained and contrasted with the fact that the capture cross section is so much larger than the geometrical cross section of the core that core penetration in practice may be ignored. The calculated results are in good agreement with available experimental data.