The GYT line list covering rotational, rovibrational and rovibronic transitions of the mercapto radical SH is presented. This work extends and replaces the SNaSH line list [Yurchenko et al., 2018, MNRAS, 478, 270] which covers the ground (electronic) $X$ $^{ 2}\Pi$ state only. This extension is prompted by the tentative identification of the ultra-violet features of SH as being of importance in the transmission spectrum of the ultra-hot Jupiter exoplanet WASP-121b [Evans et al., 2018, AJ., 156, 283]. This GYT line list model is generated by fitting empirical potential energy, spin-orbit and electronic angular momenta functions to experimentally measured wavelengths within the $X$ $^{ 2}\Pi$ and $A$ $^{ 2}\Sigma^{ +}$ states and to the $A$ $^{ 2}\Sigma^{ +}$ - $X$ $^{ 2}\Pi$ band system using ab initio curves as a starting reference point. The fits are compatible with the quoted uncertainty of the experimental data used of $\sim$ 0.03 - 0.3 cm$^{ -1}$. The GYT line list covers wavelengths longer than 0.256 $\mu$m and includes 7686 rovibronic states and 572 145 transitions for $^{ 32}$SH. Line lists for the $^{ 33}$SH, $^{ 34}$SH, $^{ 36}$SH and $^{ 32}$SD isotopologues are generated including a consideration of non-Born-Oppenheimer effects for SD. The line lists are available from the CDS (http://cdsarc.u-strasbg.fr) and ExoMol (www.exomol.com) data bases.
Categories: astro-ph.EP physics.chem-ph