Determination of lifetimes for the ν = 9, 12–16 vibrational levels of the a′ 3Σ+ state of CO and their identification from optical emission functions

The lifetimes for the a′ 3Σ+(ν = 9, 12–16) states of CO have been measured using pulsed low energy electron impact excitation and delayed coincidence detection after identification of these states was established from their optical emission function thresholds. The lifetimes determined for the ν = 12–16 vibrational levels are consistent with a v3 extrapolation of previous lifetime measurements of the lower vibrational levels. The collisional quenching cross sections were calculated from the pressure dependence of the measured lifetimes.