Measured Lifetimes of Rotational and Vibrational Levels of Electronic States of N2

Abstract

The lifetimes of vibrational levels of the B 3πg and C 3πu electronic states of molecular nitrogen and of the B 2Σu+ electronic states of the positive molecular nitrogen ion were measured by photometrically monitoring the excited level number densities in a pulsed invertron. Heavy-particle pressure damping cross sections were obtained from experimental studies of the pressure dependence of the reciprocal lifetimes. Lifetimes of individual rotational levels from K = 14 to K = 35 of the B 2Σu+(υ = 0) levels were measured. The lifetimes of all rotational levels were identical. However, our results suggest a dependence of the line strength on the rotational level different from that predicted by the Born–Oppenheimer approximation with zero rotational–vibrational interaction and zero electron spin–rotational interactions.