Charge transfer in slow collisions of C⁶⁺ with H below 1 keV∕amu

We reexamine the charge transfer cross sections for C⁶⁺+H collisions for energies below 1 keV∕amu using a fully quantum mechanical approach, based on the hyperspherical close-coupling method. Whereas most previous theoretical and experimental data agree well for the dominant charge transfer to the C⁵⁺(n=4) states, there is significant disagreement among the theories for the transition to the weaker n=5 states. Using the present quantum mechanical calculations we analyze the origin of the discrepancy among these previous calculations. We further extend the calculations to collision energies down to about 1 eV and show that electron capture to the n=5 states begins to dominate over the n=4 states.