Knowledge Bank

The FSO radical was identified by its microwave spectrum in the reaction system of carbonyl sulfide with microwave discharge products of an oxygen/$CF4$ mixture. Spectra of both the normal and $\mathrm{<mrow\; data-mjx-texclass="ORD">34</mrow>}S$ species in the ground vibrational state and of the normal species in the first excited bending state were observed in the frequency region from 30 to 80 GHz using a parallel plate Stark cell 40 cm long. Precise molecular constants including spin-rotation coupling constants and magnetic hyperfine coupling constants of the fluorine nucleus have been obtained. The dipole moment was determined to be $\mu a=0.374(12)$ D, $\mu b=1.642(9)$ D, and $\mu total=1.666(13)$ D. The molecular structure was calculated from rotational constants of the two osotopic species to be r = (S-F) -1.602(3) {\AA}, r = (S-O) =1.452(3) {\AA} and . The harmonic force field and the vibrational frequencies were estimated from observed centrifugal distortion constants and inertia defects.