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 32S12C19F2 isotopomer with J between 0 and 9, including ΔKa=2 transitions, as well as eight transitions of the 34S12C19F2 isotopomer with J between 0 and 9, have been assigned. The rotational constants and quartic centrifugal distortion constants have been determined. A 19F nuclear spin‐rotation interaction, as well as a rather large direct 19F nuclear spin–spin interaction, have been observed. The three diagonal elements of the spin‐rotation tensor at the 19F nuclei have been determined to be Maa=22.9(9) kHz, Mbb=10.4(4) kHz, and Mcc=5.4(3) kHz for 32S12C19F2 and Maa=20.9(9) kHz, Mbb=10.7(4) kHz, Mcc=6.4(4) kHz for 34S12C19F2, respectively. For 32S13C19F2, seven transitions with J between 0 and 6 have been assigned and rotational constants and two quartic centrifugal distortion constants...