MILLIMETER-WAVE AND HIGH-RESOLUTION INFRARED-SPECTRA OF D3SIBR

Millimeter-wave (mmw) spectra of (D3SiBr)-Br-79 and (D3SiBr)-Br-81 in the vibrational ground state have been recorded in the 150-650 GHz ran ge. Furthermore, mmw spectra of (D3SiBr)-Br-79 in the upsilon(3) = 1 a nd upsilon(6) = 1 states have been studied in some limited spectral ra nges. FTIR spectra of monoisotopic (D3SiBr)-Br-79 covering the bands n u(3) (a(1), 418.650 cm(-1)), nu(6) (e, 464.254 cm(-1)), nu(5) (e, 685. 367 cm(-1)), and nu(2) (a(1), 686.373 cm(-1)) have been recorded with resolutions between 2.5 and 3.5 x 10(-3) cm(-1). J-dependent round sta te parameters up to sextic tens have been determined from the mmw spec tra, and A(0) = 1.425263(12) cm(-1) for (D3SiBr)-Br-79 was derived fro m fits of several (Delta k - Delta l) = +/- 3 interactions observed in the nu(2)/nu(5) band system. While nu(3) and nu(6) interact weakly by Coriolis x, y resonance, the Coriolis resonance of the almost degener ate nu(2) and nu(5) vibrational levels is very strong. The sign of the intensity perturbation, M(2) zeta(25)M(5), is positive. Fits of the n u(3) and nu(6) bands (ca. 6000 IR lines) supplemented by mmw data and of the nu(2) and nu(5) bands (ca. 8000 lines) were obtained with rms d eviations of 0.28 and 0.37 x 10(-3) cm(-1) for the IR data. Some hot b ands of nu(3) were detected and analyzed. (C) 1997 Academic Press.