Diabatic description of electron capture by highly-charged ions from hydrogen

A diabatic formulation of electron capture by highly charged ions from atomic hydrogen at low energies is presented. This takes account of Stark mixing and polarization effects with a minimal size of basis set. The method is applied to the C4+/H system in the energy range 88-589 eV/amu. The results agree with earlier calculations based on an adiabatic formulation but do not resolve discrepancies with experiment.