First Line Lists for Triatomic Sulfur-Containing Molecules: SO and S.

We present in this paper the first room temperature rovibrational line lists for the main isotopologues of disulfur monoxide (SO) and thiozone (S) variationally computed from newly developed potential energy and dipole moment surfaces (PESs and DMSs). SO and S are supposed to be potential candidates for astronomical detection, especially in the Venusian atmosphere where sulfur chemistry plays a major role. Contrary to other stable sulfur-containing species like SO or HS, there is much less experimental data for the short-lived reactive SO and S molecules. Indeed, the infrared spectra of SO and S are quite complicated to analyze without consistent theoretical predictions because they contain both high (∼100) and a lot of hot band transitions, even at = 296 K. In this work, we have constructed PESs based on the single-reference coupled cluster approach [CCSD(T)] and including corrections due to the scalar relativistic effects, DBOC, and highly excited Slater determinants. The structure of the excited electronic states of S was also discussed. The nuclear-motion Eckart-Watson Hamiltonian expressed in terms of normal-mode irreducible tensor operators was used to compute the energy levels. For line intensity calculation, DMSs were computed at the CCSD(T)/aug-cc-pV5Z level of the theory. Rotation-vibration patterns in the fundamental bands of SO and S have been simulated taking into account the recent Fourier-transform spectra of SO recorded at the SOLEIL synchrotron. The present work aims at providing line intensities of SO and S that are missing in the literature as well as new spectroscopic support for atmospheric applications.