RESUMO
A total of 4892 transition wavenumbers of the nu(2), nu(3), nu(5), and nu(6) fundamental bands of H(3)(12)CF and 1469 frequencies of the rotational transitions in the v(2) = 1, v(3) = 1, v(5) = 1, and v(6) = 1 vibrational states have been fitted simultaneously by taking explicitly into account various Coriolis interactions, l-type interactions, and alpha-resonance terms between and within the vibrational states. The standard deviation of the fit using 71 parameters was 8.10 x 10(-5) cm(-1) for the infrared data and 0.198 MHz for the rotational data. This study clearly shows that in order to obtain a really quantitative fit of the highly precise data of vibration-rotational and rotational spectroscopy, it is necessary to fit all the data simultaneously using a variational approach. The deperturbed values of the upper state rotational constants differ significantly from those obtained previously in fitting the nu(3) and nu(6) bands as isolated bands and the nu(2)/nu(5) bands by a variational approach. This is important for the precise determination of the equilibrium structure of methyl fluoride (J. Demaison, J. Breidung, W. Thiel, and D. Papousek, Struct. Chem., in press). Besides this, the results can be used in further studies of the reduced Hamiltonians for more complicated systems of interacting vibrational levels. Copyright 1999 Academic Press.
RESUMO
A high-resolution FT infrared spectrum of H3SiF (resolution 0.0024 cm-1) in the region 620-1130 cm-1 was measured and used to analyze the fundamental bands nu2 (A1), 990.851 cm-1; nu3 (A1), 875.011 cm-1; nu5 (E), 962.213 cm-1; and nu6 (E), 729.528 cm-1. A total number of 7241 transition wavenumbers (including 53 perturbation-allowed transitions) with J'
RESUMO
A total of 6071 transition wavenumbers of the nu2, nu3, nu5, and nu6 fundamental bands of H313CF and 1689 frequencies of the rotational transitions in the v2 = 1, v3 = 1, v5 = 1, and v6 = 1 vibrational states have been fitted simultaneously by taking into account various Coriolis interactions, l-type interactions, and alpha-resonance terms between and within the vibrational states. The standard deviation of the fit using 75 parameters was final sigma = 7.63 x 10(-5) cm-1 for the infrared data and 0.150 MHz for the rotational data. The possibility of obtaining a quantitative fit of the very precise data of high-resolution Fourier transform and submillimeter-wave spectroscopy for a semirigid symmetric top molecule is discussed. Copyright 1998 Academic Press.
