High Resolution Spectroscopy of N₃ by Laser Induced Fluorescence

The azide radical was generated in the gas‐phase photolysis of HN 3 and detected by the high resolution laser induced fluorescence (LIF) technique. Rotationally resolved spectra of the à 2 Σ u 000 ← X̃ 2 Π g 000 and à 2 Σ u 010 → X̃ 2 Π g 010 transitions were obtained. Analysing single rotational lines, the spin splitting constant of the à 2 Σ u 000 state was derived to be γ = (1.35 ± 0.05) · 10 −3 cm −1 . Evidence was obtained for a lifetime τ of the à 2 Σ u 000 state of 0.37 ≤ τ ≤ 20 ns. The observed narrow linewidths are important in other experiments where the determination of scalar and vector properties allows an elucidation of reaction and photodissociation dynamics.