The state-selective non-dissociative single-electron capture reactions of 6 keV CO2+ ions from rare gas (He, Ne, Ar, Kr, Xe) targets are investigated by translational energy spectroscopy. Capture from CO2+ (3Π) into doublet states of CO+ dominates. However, there are firm indications for the involvement of electronically excited CO2+ (1.7 eV above CO2+ (3Π) in the projectile beam, and also for the formation of quartet states of CO+. Landau-Zener reaction windows, derived specifically for atomic ion-atom systems, are applied to this diatomic dication-atom series, giving excellent agreement with experiment.