Fourier-transform microwave spectrum, structure, harmonic force field, and hyperfine constants of sulfur chloride fluoride, ClSF

Abstract

The rotational spectrum of sulfur choride fluoride, ClSF, has been observed for the first time in the frequency range 8–26 GHz by means of a pulsed molecular jet Fourier-transform microwave spectrometer. The unstable sample molecule has been prepared using a pulsed electrical discharge in jets containing a mixture of SF6 and SCl2 in Ne. Besides the parent species 35Cl32S19F, the isotopomers 37Cl32S19F and 35Cl34S19F could be observed in natural abundance. Rotational constants and quartic centrifugal distortion constants as well as nuclear quadrupole coupling constants due to 35Cl and 37Cl and spin–rotation constants due to 35Cl, 37Cl, and 19F are given. The data were used for the determination of r0, rΔP, rs structural parameters. Additionally, the new data were used for the refinement of the molecular harmonic force field. Results from those harmonic force field calculations were applied in the evaluation of the ground-state average structure, rz, and the estimation of the equilibrium structure, re. The rs structure is r(SF)=160.653(162) pm, r(SCl)=199.437(65) pm, and ∠(ClSF)=100.732(81)°. The diagonal elements of the 35Cl/37Cl quadrupole coupling tensors have been obtained, and are interpreted in terms of the bonding at 35Cl/37Cl. Negative 19F spin–rotation constants suggest a close analogy of the electronic structures of ClSF and SF2.