THE $\nu_{1}$ BAND OF HOBr

Author Institution: California Institute of Technology, Pasadena, California 91109.; Chalk River Laboratories, Chalk River, Ontario KOJ IJO, Canada.; "Faculty of Science, National University of Singapore", Lower Kent Ridge Road, Singapore 0511, Singapore.; National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada.; National Research Council of Canada, Ottawa, Ontario K1A 0R6, Canada.The $\nu_{1}$ band of HOBr centered at $3614.903 cm^{-1}$ has been observed at $0.006 cm^{-1}$ resolution. The band is a hybrid type with $|(\partial_{\mu_{b}}/\partial Q_{1})/(\partial_{\mu_{a}}/\partial Q_{1})\approx 0.84$. The spectra of both bromine isotopes have been simultaneously fitted with a single calculation which includes all the previously reported rotational transitions. There appear to be no strong local perturbations to complicate the fitting of the line positions. There is a prominent Herman-Wallis effect for the b-type transitions which is well described by linear and quadratic terms in $K_{a}$. Precise parameters for the upper states and improved parameters for the ground states of both species will be presented as will the Herman-Wallis factor. The rotational constants for the ground state and all three fundamental vibrations will be summarized and the equilibrium structure will be shown