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

Abstract

The lifetimes of vibrational levels of the $B^3{\pi }_g$ and $C^3{\pi }_u$ electronic states of molecular nitrogen and of the $B^2{\Sigma }_u^{+}$ 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 $\text{K\hspace{0.17em}=\hspace{0.17em}14}$ to $\text{K\hspace{0.17em}=\hspace{0.17em}35}$ of the $B^2{\Sigma }_u^{+}\text{(υ\hspace{0.17em}=\hspace{0.17em}0)}$ 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.