THE MICROWAVE-SPECTRUM, SPIN-ROTATION COUPLING-CONSTANTS, AND STRUCTURE OF THIOCARBONYL FLUORIDE, SCF2, OBSERVED WITH A CAVITY MICROWAVE FOURIER-TRANSFORM SPECTROMETER

The microwave spectrum of thiocarbonyl fluoride, SCF2, has been investigated in the frequency range of 6.7-18.4 GHz using a pulsed molecular-beam microwave Fourier transform spectrometer. Twelve a-type transitions of the (SCF2)-S-32-C-12-F-19 isotopomer with J between 0 and 9, including DELTA-K(a)=2 transitions, as well as eight transitions of the (SCF2)-S-32-C-12-F-19 isotopomer with J between 0 and 9, have been assigned. The rotational constants and quartic centrifugal distortion constants have been determined. A F-19 nuclear spin-rotation interaction, as well as a rather large direct F-19 nuclear spin-spin interaction, have been observed. The three diagonal elements of the spin-rotation tensor at the F-19 nuclei have been determined to be M(aa) = 22.9(9) kHz, M(bb) = 10.4(4) kHz, and M(cc) = 5.4(3) kHz for (SCF2)-S-32-C-12-F-19 and M(aa) = 20.9(9) kHz, M(bb) = 10.7(4) kHz, M(cc) = 6.4(4) kHz for (SCF2)-S-32-C-12-F-19 respectively. For (SCF2)-S-32-C-13-F-19, seven transitions with J between 0 and 6 have been assigned and rotational constants and two quartic centrifugal distortion constants have been derived. The splitting patterns due to the two F-19 nuclei and the C-13 nucleus have been observed but not completely resolved. A ground-state average structure has been determined for (SCF2)-S-32-C-12-F-19 as r(z)(CS) = 1.5870(20) angstrom, r(z)(CF) = 1.3182(13) angstrom, and a spherical angle (FCF) = 106.89 (11)-degrees.