ABSTRACT
A large number of rotational transitions of 32S16O2, 34S16O2, and 32S18O16O have been measured in the mm-, submm-, and terahertz ( approximately 1 THz) spectral regions. These data sets have been combined with all previously measured SO2 microwave and selected far infrared data to obtain a highly precise set of ground state rotational constants for these isotopomers. The rotational constants for the three isotopomers are in MHz as follows: Parameter32S16O234S16O232S18O16O A60778.54977 (44)58991.18295 (51)59101.1690 (27) B10318.07348 (7)10318.50993 (9)9724.64284 (56) C8799.703399 (70)8761.302481 (97)8331.56018 (51) Centrifugal distortion constants up to P10 are included in the fit. A frequency listing of all the data used in the frequency range between about 7 GHz and 1 THz is included. Copyright 1998 Academic Press.
ABSTRACT
We report here how we have incorporated the effects of a nonzero total electron spin in the MORBID Hamiltonian and computer program [P. Jensen, J. Mol. Spectrosc. 128, 478-501 (1988); J. Chem. Soc. Faraday Trans. 2 84, 1315-1340 (1988); in "Methods in Computational Molecular Physics" (S. Wilson and G. H. F. Diercksen, Eds.), Plenum Press, New York, 1992] for calculating the rovibronic energies of a triatomic molecule directly from the potential energy function. The spin-spin and spin-rotation Hamiltonian terms, given in a form depending on the vibrational coordinates, have been expressed in terms of isotope-independent functions and added to the MORBID rotation-vibration Hamiltonian. The eigenvalues of the resulting Hamiltonian are obtained in a variational procedure. This method is tested on the methylene radical CH2 in the X ; 3 B 1 electronic ground state for which we describe simultaneously the splittings due to electron spin for the isotopomers 12 CH2 , 12 CD2 , and 13 CH2 . For these molecules, experimental data are available, and we compare the results of least-squares fits to these data with predictions from ab initio theory.
ABSTRACT
In the present work, we study the spectrum of the H2Te molecule in the submillimeter-wave and far infrared region. An important aim of this investigation is the further experimental characterization of the anomalous "four-fold cluster effect" exhibited by the rotational energy levels in the vibrational ground state of H2Te. The spectrum in the region 90-472 GHz was measured with a source-modulated millimeter-wave spectrometer and that between 600 and 1600 GHz with a far-infrared sideband spectrometer. The far infrared spectrum from 30 to 360 cm-1 was measured with a Bruker IFS 120 HR interferometer attached to a 3 m long cell. We have assigned 224 submillimeter-wave lines and 1695 FIR lines. These observed data were supplemented by a large number of ground state combination differences derived from rotation-vibration bands of H2Te, and the resulting large data set was analyzed by means of a modified Watson Hamiltonian. Accurate sets of rotational and centrifugal distortion constants for all eight tellurium isotopomers were obtained.
