15min:

F. K. TCHANA, J. ORPHAL, I. KLEINER, CNRS, Laboratoire de Photophysique Moléculaire, 91405 Orsay Cedex, France; B. REDLICH, Institut für Anorganische Chemie, Universität Münster, 48149 Münster, Germany; D. SCHEFFLER, H. WILLNER, Institut für Anorganische Chemie, Universität Duisburg, 47048 Duisburg, Germany; R. MBIAKE, Centre de Physique Atomique Moléculaire et Optique Quantique, Université de Douala, Cameroun; O. BOUBA, Université de Ngaoundéré, Cameroun.

Nitryl bromide, BrNO₂, is produced in the marine troposphere by heterogeneous reactions between nitrogen oxides and bromine containing aerosols. Its peak concentrations reach values of several 10⁷ cm^-3. In polluted coastal areas, therefore, BrNO₂ is an important species in the release of bromine from the ocean into the atmosphere.

The ₂ fundamental bands of ⁷⁹BrNO₂ and ⁸¹BrNO₂, located around 787 cm^-1 (12.7 µm), were recorded using a high-resolution Fourier-transform infrared spectrometer. A total of nearly 5000 transitions with J\le 80 and K_a\le 30 were reproduced using a Watson-type A-reduced Hamiltonian with a root-mean-square deviation of better than 5× 10^-4 cm^-1. Rotational and centrifugal distortion constants for the v₂ states have been determined, as well as an improved set of ground state constants for both isotopomers. Due to their sharp Q branches falling into an atmospheric window, the ₂ bands might be useful for future attempts to detect atmospheric BrNO₂.