Rotational spectra of hydrazoic acid

Hydrazoic acid is a quasi-linear molecule with typical strong perturbations among rotational levels in different vibrationally excited states. The rovibrational interactions among the ground and the two lowest vibrationally excited states v(5) and v(6) make the line assignments very complicated. Overall 446 new rotational transitions were measured and assigned to rovibrational quantum numbers. This new dataset contains 194 transitions from the ground state, 160 and 92 transitions from the vibrationally excited v(s) and v(6) states, respectively. The rotational data set is extended up to K-a = 8 for the ground state, K-a = 7 for v(5), and Ka = 3 for vs. The frequencies of these new rotational lines, along with the data from previous sub millimetre and infrared studies were quantitatively analysed. The level crossings among ground and vibrationally excited v(5) and v(6) states and the corresponding rovibrational interactions were described in detail. (C) 2017 Elsevier Inc. All rights reserved.