The radiative lifetime of N2(a 1Πg, v=0–2)

We have employed direct two-photon laser excitation of specific vibrational levels of N2(a 1 Πg) to measure the lifetime of this state. Direct observation of emission from the a 1Πg –X 1∑+g transition in a large cell was employed to follow fluorescence decays. Experiments were conducted to verify that the effects of collisional transfer and diffusion were not contributing to the observed lifetime. Our experiments showed that the radiative lifetime of vibrational levels 0–2 is 56±4 μs and is independent of vibrational level, within experimental error. The observed lifetimes are in good agreement with recently reported theoretical calculations.