The Microwave Spectrum of a Slightly Aspherical Top—The Structure and Dipole Moment of Sulfuryl Fluoride

The microwave spectrum of the slightly aspherical rotor, sulfuryl fluoride, has been investigated. Seven lines were found in the twenty to thirty thousand megacycle region. Six of these lines were assigned to J=1→2 and 2→3 rotational transitions of the molecule S32O2F2 and the other to the 111→212 transition of S34O2F2. These lines can be fitted to within the limits of experimental error (0.002 percent) with the following reciprocal moments of inertia: a32=5139.77 mc a34=5139.77 mcb32=5077.81 mc b34=5073.00 mcc32=5057.22 mc c34=5052.51 mc Structural parameters were determined from these moments and the assumption of C2v symmetry. The latter was confirmed by intensity measurements. S–O 1.370±0.01A S–F 1.570±0.01A O–S–O angle 129∘38′±30′ F–S–F angle 92∘47′±30′The S–O distance differs by −0.06A from the published electron diffraction value. Measurements on stark lobes of the three 1→2 transitions of S32O2F2 gave a quantitative check of the assignment and a value of 0.228 Debye units for the dipole moment.