Radiative lifetimes and pressure dependence of the relaxation rates of some vibronic levels in N2+, N2, CO+, and CO

Radiative lifetimes of the B2Σu+(ν′ = 0) level in N2+, the C 3πu (ν′ = 0, 1, 2) levels in N2, the B1Σ+(ν′ = 0) and C1Σ+(ν′ = 0) levels in CO, and the B2Σ+(ν′ = 0, 1) levels in CO+ have been measured to be 60.4 ± 0.4, 40.4 ± 0.5, 40.6 ± 0.5, 38.5 ± 0.6, 23 ± 3, 2.2 ± 0.8, 53.6 ± 0.7, and 64.1 ± 0.8 nsec, respectively. The measurements were made by studying the time distribution of photons emitted in the decay of these levels after collisional excitation by a pulsed-proton beam. The apparent lifetime of the levels was studied as a function of target pressure over a range 1–200 mtorr. Collisional quenching and resonance trapping were observed in varying degrees. The radiative lifetimes are derived from the extrapolated zero pressure relaxation rates, and ν′ - progression transition probabilities are determined by using our measured B-A and C-A electronic branching ratios in CO, and the CO+ band strength measurements of Judge and Lee.