New high-resolution analysis of the ν1 + 3ν3 band of nitrogen dioxide in the near infrared spectral region

The high-resolution Fourier-transform absorption spectrum of the 14N16O2 molecule was recorded in the near infrared 5200-6005 cm−1 spectral range. Starting from the results of a previous study [R.E. Blank, M.D. Olman, C.D. Hause, J. Mol. Spectrosc. 33 (1970) 109-118] a new analysis of the ν1 + 3ν3 band located at 5984.705 cm−1 has been performed. The new assignments involve energy levels of the (1 0 3) vibrational state with rotational quantum numbers up to Ka = 8 and N = 47. The spin-rotation energy levels were satisfactorily reproduced within their experimental uncertainty using a theoretical model which takes explicitly into account the Coriolis interactions between the spin-rotational levels of the (1 0 3) vibrational state and those of (1 2 2) and of (0 8 0), the anharmonic interactions between the (1 2 2) and (0 8 0) vibrational states together with the electron spin-rotation resonances within the (1 0 3), (1 2 2) and (0 8 0) vibrational states. As a consequence, precise vibrational energies, rotational, spin-rotational, and coupling constants were obtained for the triad {(1 2 2), (0 8 0), (1 0 3)} of interacting states of 14N16O2. Using these parameters a comprehensive list of line positions and of reliable line intensities was generated for the ν1 + 3ν3 band of NO2.