Observation of the formation of C+, O+, and ArC+ in the collisions of Ar+(2P3/2,1/2) with CO

Absolute total cross sections for the formation of C+ , O+ , and ArC+ in the collisions of Ar+ (2 P3/2,1/2 )+CO have been measured over the center-of-mass collision energy (Ec.m. ) range of ∼4–123 eV. The observed appearance energies for C+ and O+ are in agreement with the thermochemical thresholds for the C+ (2 P)+O(3 P) and O+ (4 S0 )+C(3 P) product channels, respectively. The cross sections for C+ are significant compared to those for CO+ . At Ec.m. =12.9 eV, the analysis of the kinetic energy distributions of C+ and CO+ supports the conclusions that many excited vibronic states of CO+ are populated and that the C+ ions are formed by predissociation of electronic excited CO+ .