Microwave spectrum of sulfuryl chloride fluoride, SO₂ClF: structure, hyperfine constants and harmonic force field

Abstract

The pure rotational spectrum of sulfuryl chloride fluoride, SO,CIF, has been investigated in the frequency range 5.6-24.0 GHz using a pulsed molecular beam microwave Fourier-transform spectrometer. Between 48 and 170 lines of 8 to 26 rotational transitions have been observed for the six isotopomers SO,CIF, SO, 37CIF, 34S0,CIF, 34S0, 37CIF, SO'80CIF and SO " 0 37CIF (unlabelled atoms indicate l60, "F, 32S and 35CI) in natural isotopic abundance. The rotational and quartic centrifugal distortion constants have been determined. ro I T A P and r,-type structural parameters have been evaluated. A harmonic force field has been calculated to derive ground-state average and estimated equilibrium geometries. The description of the normal modes in terms of internal coordinates is discussed. Chlorine and fluorine hyperfine structures have been resolved, allowing quadrupole coupling (including zbc for the isotopomers containing " 0 ) and spin-rotation constants to be determined. Variations in the chlorine quadrupole coupling constants with different isotopomers have allowed the CI quadrupole tensor to be diagonalized and indicate that its z-axis coincides with the SCI bond.Although sulfuryl chloride fluoride, SO,ClF, has been known for more than 50 years,' there is only one study, by Holt and Gerry, reporting its structure in the gas phase., Using a conventional Stark modulated microwave spectrometer, they determined rotational constants, chlorine quadrupole coupling constants and an effective distortion constant for each of the two most abundant isotopomers, S0,ClF and SO, 37ClF (unlabelled atoms indicate l60, 19F, 32S and 35Cl). By assuming values for r ( S 0 ) and L(C1SF) from a comparison with the related molecules sulfuryl fluoride, SO,F,, and sul-fury1 chloride, S02C12, they were able to derive the remaining geometrical parameters.Recently Gombler investigated 32/34S isotopic shifts of the "F NMR frequency of sulfur-and fluorine-containing comp o u n d ~. ~ From these results he suggested that the SF bond in S 0 2 F 2 should be longer than that in SO,ClF, in contrast to the conclusions from the microwave studies. More recently a single-crystal X-ray diffraction study of S0,XY (X, Y = C1, F) at low temperatures has yielded the precise geometrical parameters of these compounds in the solid state.4Raman and IR spectra have also been re~orded.'.~ In addition, Pfeiffer obtained a force field of S0,ClF by transferring force constants and structural parameters from S02C1, and S02F2.7 These force constants reproduced most of the observed vibrational wavenumbers moderately well. Better agreement was obtained when the assignments of two pairs of fundamentals in ref. 5 were exchanged. In addition, the earlier assignment of the v6 band' was rejected and it was assumed that this fundamental is overlapped by v9. The assignments of Pfeiffer have been confirmed in a recent reinvestigation of the Raman and IR spectra.'At room temperature the microwave spectrum of S0,ClF is very dense, with many transitions between rotational levels at ...

Rotational spectroscopy of isotopic cyclopropenone, c-H2C3O, and determination of its equilibrium structure

“…a given molecule. The advantage of taking i into account explicitly is that rotational parameters of isotopic species to be studied can be estimated much more accurately, in particular for atoms with more than two isotopes or for multiply substituted isotopologs (Epple & Rudolph 1992;Müller & Gerry 1994;Müller et al 2019), if residuals of known isotopologs can be transferred to the values of the desired isotopolog. In the case of H 2 CS, Müller et al (2019) extrapolated the residuals of H 2 C 32 S, H 2 C 33 S, and H 2 C 34 S to H 2 C 36 S, and those of H 2 C 32 S, H 2 C 34 S, and H 13 2 CS to H 13 2 C 34 S. The equilibrium (or r e ) structure of a molecule in the potential minimum is the most meaningful structure.…”

Electron collision with sulfuryl chloride (SO2Cl2) molecule

“…A comparison of selected properties for SO 2 -containing molecules (X, Y = F, Cl; cf figure3); interatomic distances and angles in sulfuryl halides are from[49].…”

Laboratory spectroscopic study of isotopic thioformaldehyde, H2CS, and determination of its equilibrium structure

“…We derived an r I, structure (Rudolph 1991), see also Sect. 6, from the known rotational parameters because this structure model can provide good predictions of rotational parameters of isotopologs not yet studied, see, e.g., the example of cyclopropylgermane (Epple & Rudolph 1992) or sulfuryl chloride fluoride (Müller & Gerry 1994). We were able to make assignments of R-branch transition up to K a = 5 for both isotopic species, however, those for H 13 2 C 34 S were only made in the process of writing this manuscript, and assignments extend only up to 362 GHz.…”

“…According to Rudolph (1991), the r I, parameters are equivalent with r ∆I parameters (isotopic differences are fit to determine structural parameters) and with substitution parameters r s (isotopic differences between one reference isotopolog and one isotopolog in which one atom has been substituted are used to locate that atom). The advantage of considering the i explicitely in the calculations are predictions of rotational parameters of isotopic species to be studied, see for example Epple & Rudolph (1992) and Müller & Gerry (1994). The resulting structural parameters are given in Table 7 together with earlier r s parameters, ground state average (r z ) parameters and an approximation of the equilibrium structure derived from r z parameters.…”