Martin-Drumel, M. A., Roucou, A., Brown, G. G., Thorwirth, S., Pirali, O., Mouret, G., Hindle, F., McCarthy, M. C., and Cuisset, A. 2016. "High resolution spectroscopy of six SOCl2 isotopologues from the microwave to the far-infrared." Journal of Chemical Physics 144:084305. https://doi.org/10.1063/1.4942024
Despite its potential role as an atmospheric pollutant, thionyl chloride, SOCl2, remains poorly characterized in the gas phase. In this study, the pure rotational and ro-vibrational spectra of six isotopologues of this molecule, all detected in natural abundance, have been extensively studied from the cm-wave band to the far-infrared region by means of three complementary techniques: chirped-pulse Fourier transform microwave spectroscopy, sub-millimeter-wave spectroscopy using frequency multiplier chain, and synchrotron-based far-infrared spectroscopy. Owing to the complex line pattern which results from two nuclei with non-zero spins, new, high-level quantum-chemical calculations of the hyperfine structure played a crucial role in the spectroscopic analysis. From the combined experimental and theoretical work, an accurate semi-experimental equilibrium structure (reSE) of SOCl2 has been derived. With the present data, spectroscopy-based methods can now be applied with confidence to detect and monitor this species, either by remote sensing or in situ.