The rotational spectra, isotopically independent parameters, and interatomic potentials for the X-1 (2)Pi(3/2) and X-2 (2)Pi(1/2) states of BrO

Observations of the rotational spectrum of BrO have been extended to includ e vibrational levels up to v = 8 in the X-1 (2)Pi (3/2) and v = 7 in the X- 2 (2)Pi (1/2) states. The rotational spectra of isotopically enriched (BrO) -O-18, X-1, v = 0, 1 and X-2, v = 0 have been observed as well. The spectra of all four isotopic species have been fit to a Hamiltonian in which the p arameters have fixed isotopic ratios. An extensive set of isotopically inde pendent parameters has been determined. Interatomic potentials have been de rived for both the X-1 and X-2 states. The hyperfine constants and their vi brational dependencies have been determined more precisely and several of t hem have been determined for the first time. These are interpreted in terms of the electronic structure of the molecule. The isotope relations among t he constants have provided a means of decorrelating the electron spin-rotat ion constant gamma from the fine-structure centrifugal distortion constant, A(D), and have allowed the first determination of an effective value for g amma. (C) 2001 Academic Press.