Rotation-vibration spectrum of hydrazoic acid in the near infra-red and in the visible

Abstract

Second and third overtones of N—H stretching vibration in HN₃ have been investigated at higher resolving power and pathlength than previously, and the fourth overtone photographed for the first time. The rotational analysis of 3ν₁, where more than 500 lines were measured, gives accurate values of the rotational constants of both ground and upper states. A local perturbation was found in levels with K′= 2 and 4. The rotational analysis of 4ν₁, where lines are broader than in 3ν₁, indicates that the dependence of A from vibrational quantum number v₁, is not linear. Owing to the large linewidth (∼0.35 cm^–1) only the analysis of the K-structure is possible for 5ν₁. The diffuseness in 4ν₁ and 5ν₁ is discussed in terms of line broadening by case II predissociation.