Laser measurements of the radiative lifetime of the B2Σ+ state of CN

A tunable dye laser has been used to measure the radiative lifetime of the individual rotational levels of the B2Σ+ state of CN. The radiative lifetime of the unperturbed rotational levels is 65.6±1.0 nsec, in agreement with previous workers. A longer radiative lifetime of 72±1 nsec is observed for the K′ = 4 level of the B state. The measured values of the perturbed and unperturbed levels support the longer lifetimes for the A2Π state of CN. The quenching cross section of the B2Σ state of CN is 41±20 Å2 and is independent of the rotational energy of the B state.