Rotational excitation of ions produced by the He(2 3S) Penning ionization of CO and N2

Rotational-state distributions of the CO+ (A–X, B–X) and N2+(B–X) emissions produced by the collisions of He(2 3S) with CO and N2 were studied in the collision energy (ER range 100–200 meV. The rotational populations of the emitting states can be fitte by single Boltzmann temperatures (TR. The TR (320 ± 30 K) for the ν′ = 3 and 4 levels of the CO+ (A2Π) state are nearly independent of, or slightly increase with, ER, while TR for the CO+(B2Σ+, ν′ = 0) state increases rapidly with ER.The TR (430 ± 20 K) for the N2+(B2Σ+, ν′ = 0) state is nearly independent or slightly decreases with increasing ER. Interactions providing these trends are discussed.