K-shell resonant transfer and excitation in calcium ions

We have calculated K-shell cross sections for the process of resonant transfer excitation followed by x-ray stabilization (RTEX) in collisions of ${\mathrm{Ca}}^{\mathit{q}+}$ (q=10–12,16–19) ions with ${\mathrm{H}}_2$. Our KLn intermediate-coupling results are in excellent agreement with the experimental results of Tanis et al. [Phys. Rev. A 34, 2534 (1986)] for q=16–18, particularly when supplemented by our LS-coupling results for the KMn transitions. The comparison for q=19 is hampered by the nonresonant background, but our results are consistent with experiment. Our LS-coupling results for KLn-plus-KMn transitions are in good agreement with experiment for q=11 and 12. But for q=10 our KMn RTEX cross sections are much smaller than the sparse experimental results, indicating a large nonresonant experimental background.