Single electron capture for impact of (0.5-9 keV) C²⁺on He, Ar and H₂

Absolute total cross section measurements and state-selective translational energy spectroscopy have been performed for single electron capture by 0.5-9 keV C 2+ from H 2 , He and Ar, for the C 2+ ground state as well as the C 2+ metastable state. The experimental results are compared with available data obtained with undefined metastable primary ion beam fractions. For the particular case of C 2+ -H 2 collisions, experimental results could be explained by close-coupling calculations involving empirically derived coupling matrix elements and Franck-Condon factors for H 2 ionization via electron capture.