New line positions analysis of the 2ν 1 and ν 1 + ν 3 bands of NO2 at 3637.848 and 2906.070 cm−1

Abstract

Using a high-resolution Fourier transform spectrum recorded at SOLEIL for a rather large value of the (pressure × path length) product a new investigation of the very weak 2ν 1 absorption band of nitrogen dioxide, located at 2627.377 cm−1 was performed, together with an extension up to higher N and Ka values of a previous investigation of the strong ν 1 + ν 3 band [J.-Y. Mandin, V. Dana, A. Perrin, J.-M. Flaud, C. Camy-Peyret, L. Régalia and A. Barbe, J. Mol. Spectrosc. 181, 379 (1997)]. The 2ν 1 lines proved to be perturbed by local vibration–rotation resonances which couple the (2,0,0) energy levels with those of the (1,2,0) and (1,0,1) states. Also the (1,0,1) energy levels are also coupled by a C-type Coriolis resonance with those of the (1,2,0) and (2,0,0) energy levels. The final energy levels calculation involves six interacting states of NO2, {(2,0,0), (1,2,0), (1,0,1), (0,0,2), (0,4,0), (0,0,2)}. An estimation of line intensities parameters was performed for the very weak 2ν 1 band. Finally a list of line parameters (positions, intensities and shapes) for the 2ν 1, ν 1 + 2ν 2 and ν 1 + ν 3 bands of NO2, was generated and is now included in the GEISA database (https://geisa.aeris-data.fr/).