6533b85bfe1ef96bd12ba938

RESEARCH PRODUCT

The rotational gas-phase spectrum of trans- and cis-HSSOH at 100GHz

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Abstract We present the first pure rotational spectra of the two most stable conformers of oxatrisulfane, trans- and cis-HSSOH, in their vibrational ground state. For both conformers a-, b-, and c-type transitions have been recorded in the range from 75 to 120 GHz using an all solid-state spectrometer. More than 200 lines have been assigned for each conformer, most of them belonging to the r Q 2 - and the r Q 3 -branch of the perpendicular spectra. The least-squares fit analysis using a semirigid rotor Hamiltonian in S-reduction yields precise values for the ground-state rotational constants A 0 = 21 145.93422 ( 66 ) , B 0 = 4479.92301 ( 21 ) , C 0 = 3828.34269 ( 21 ) for cis-HSSOH, and A 0 = 21 071.08204 ( 75 ) , B 0 = 4490.04249 ( 34 ) , C 0 = 3833.20651 ( 35 ) for trans-HSSOH as well as centrifugal distortion parameters of quartic and sextic order. The ratio of the permanent dipole moment components μ b / μ c = 0.29 ( 3 ) for cis-HSSOH and μ b / μ c = 0.99 ( 3 ) for trans-HSSOH has been derived from measured line intensities. All experimentally derived molecular parameters are in very good agreement with high-level quantum-chemical calculations using coupled-cluster techniques, thus confirming the current understanding of the structure of oxasulfanes.