Excitation of the B 3Pi/subg/ states of N2 by electron impact

Radiative lifetime measurements of 13 vibrational levels of the B 3Pi/subg/ state of N2 have been obtained at 50 eV incident electron energy and 30 mTorr N2 gas pressure using a 50-μsec electron excitation pulse. Two radiative decay components with lifetimes of approximately 5 and 25 μsec are observed in each case. The short-lived component is identified as the contribution from direct excitation of the B 3Pi/subg/ state. The long-lived cascade contribution is observed to decrease from 37% of the total B 3Pi/subg/→A 3Σ/subu/+(v', v'') radiation for the v' = 0 vibrational level to 15% for the v' = 12 level and is consistent with theoretical predictions by Cartwright et al