The potential energy and dipole moment surfaces of HOBr

A theoretical study of the spectroscopy of HOBr and its deuterated isotopomer is presented. Highly accurate ab initio potential energy and dipole moment surfaces have been determined at the multireference configuration interaction level of theory, with large triple-ζ quality basis sets. From the analytic expression of the PES, a quartic anharmonic force field is derived, which, after a little empirical adjustment on the harmonic part, is used to evaluate spectroscopic parameters by means of standard perturbative formulae. Comparisons with experiment and previous computations are made.