The Coriolis Interaction between the v2 = 1 and v3 = 2 States of Nitrosyl Bromide: Anomalous Quadrupole Patterns and Interstate Transitions in the Millimeter-Wave Spectrum.
The millimeter-wave rotational spectra of 79BrNO and 81BrNO in the v2 = 1 and v3 = 2 vibrational states have been reinvestigated. Measurements of the rotational spectrum in the region of maximum c-type Coriolis interaction between the two states allowed the previous analysis to be extended to account for some uncommon effects. For the most perturbed transitions the nuclear quadrupole hyperfine structure arises from coupling of not only the bromine nucleus, but also the nitrogen nucleus with the rotational angular momentum. These effects were satisfactorily fitted with a Hamiltonian describing Coriolis coupling in a molecule with two quadrupolar nuclei. The successful analysis of pure rotational transitions then allowed accurate prediction of rovibrational transitions, six of which were measured for 79BrNO and four for 81BrNO. Copyright 1998 Academic Press.
High resolution Fourier transform infrared spectrum of 79Br 14N 18O: analysis of the ? 1 band
Abstract The first high-resolution Fourier transform infrared spectrum of the ν 1 fundamental band of the 79 Br 14 N 18 O isotopic species of nitrosyl bromide located at 1751.29495(2) cm −1 has been analyzed. Using the Watson-type A-reduced Hamiltonian, the study of the rovibrational transitions has been performed. Rotational constants, quartic and sextic centrifugal distortion terms for the ν 1 =1 and for the vibrational ground state have been derived. The ground state parameters obtained in this work have been compared to the corresponding constants determined by an empirically refined MRCI (MultiReference Configuration Interaction) force field available in the literature.
Microwave Spectrum and Molecular Constants of Nitrosyl Bromide
The microwave spectrum of NOBr has been studied in the region 20 000 to 40 000 Mc/sec and an analysis made of the J = 2→3 transition. The following molecular constants were obtained. NOBr79NOBr81Rotational constants (Mc/sec)A83 34083 340B3747.243722.49C3586.003563.34Asymmetry parameterb−0.001012−0.000998Quadrupole coupling components (Mc/sec)χaa  388.3  325.5χbb−239.5−200.2χcc−148.8−125.3 The structural parameters obtained from these are d(N–O) = 1.15 A, d(N–Br) = 2.14 A, d(O–Br) = 2.81 A, and ∠Br–N–O = 114°. The interatomic distances are compared with electron diffraction results, and a brief interpretation of the quadrupole coupling in terms of chemical bonds is given.