Journal of Physical Chemistry A, Vol.112, No.49, 12616-12621, 2008
Dimers of Fluorinated Methanes with Carbonyl Sulfide: The Rotational Spectrum and Structure of Difluoromethane-OCS
The pure rotational spectra of four isotopologues of the difluoromethane-carbonyl sulfide dirtier have been measured in the 5-15 GHz region with use of pulsed-nozzle Fourier-transform microwave spectroscopy. The complex was determined to possess an ab plane of symmetry with a center of mass separation of 3.41(2) angstrom and dipole moment components mu(a) = 1.1386(18) D, mu(b) = 0.4840(63) D, mu(tolal) = 1.2372(41) D. Experimental planar moments indicate that the two fluorine atoms straddle the symmetry plane while one of the C-H bonds of the difluoromethane monomer is aligned to interact with the oxygen atom of the OCS molecule. The assignment of the rotational spectrum for this dimer completes the experimental studies of the series of dimers involving fluorinated methanes (HCF3, H2CF2, and H3CF) complexed with OCS and makes possible a comparison of properties within this series.