ExoMol molecular line lists – XXVI: spectra of SH and NS

Abstract

Line lists for the sulphur-containing molecules SH (the mercapto radical) and NS are computed as part of the ExoMol project. These line lists consider transitions within the X 2 Π ground state for 32 SH, 33 SH, 34 SH and 32 SD, and 14 N 32 S, 14 N 33 S, 14 N 34 S, 14 N 36 S and 15 N 32 S. Ab initio potential energy (PEC) and spin-orbit coupling (SOC) curves are computed and then improved by fitting to experimentally observed transitions. Fully ab initio dipole moment curves (DMCs) computed at high level of theory are used to produce the final line lists. For SH, our fit gives a root-meansquare (rms) error of 0.03 cm −1 between the observed (v max = 4, J max = 34.5) and calculated transitions wavenumbers; this is extrapolated such that all X 2 Π rotationalvibrational-electronic (rovibronic) bound states are considered. For 32 SH the resulting line list contains about 81 000 transitions and 2 300 rovibronic states, considering levels up to v max = 14 and J max = 60.5. For NS the refinement used a combination of experimentally determined frequencies and energy levels and led to an rms fitting error of 0.002 cm −1 . Each NS calculated line list includes around 2.8 million transitions and 31 000 rovibronic states with a vibrational range up to v = 53 and rotational range to J = 235.5, which covers up to 23 000 cm −1 . Both line lists should be complete for temperatures up to 5000 K. Example spectra simulated using this line list are shown and comparisons made to the existing data in the CDMS database. The line lists are available from the CDS (http://cdsarc.u-strasbg.fr) and ExoMol (www.exomol.com) data bases.

Aluminium oxide in the atmosphere of hot Jupiter WASP-43b

“…It should be noted that this dip is less pronounced with the Spitzer data analysed by Morello et al (2019). Other molecules that exhibit a similar dip at 3.6 µm and increased absorption at 4.5 µm include SiO (Barton et al 2013), AlF , CaF (Hou & Bernath 2018), LiCl (Bittner & Bernath 2018), NS (Yurchenko et al 2018b), PO, and PS (Prajapat et al 2017). The current data availability for these molecules is discussed in Sect.…”

“…4.3, which could potentially be used to explain the Spitzer data points, the line list data for SiO (Barton et al 2013), AlF , and CaF (Hou & Bernath 2018) are currently not computed up to a high enough energy (relating to a low enough wavelength) to cover the region of the WFC3 data, or into the visible. The line list data for NS (Yurchenko et al 2018b), PH (Langleben et al 2019), and PS (Prajapat et al 2017) do already cover the WFC3 wavelength region; however, there are no significant absorption features that can be used to detect these molecules in this region. The ExoMol group (Tennyson et al 2016, and in prep.…”

The PHOENIX Exoplanet Retrieval Algorithm and Using H− Opacity as a Probe in Ultrahot Jupiters

“…More information on the opacities used that are relevant to exoplanet modeling can be found in Lothringer et al (2018) and Lothringer & Barman (2019). New line lists are currently being incorporated into PHOENIX and PETRA, including HITEMP H 2 O and CO 2 (Rothman et al 2010), AlO (Patrascu et al 2015), TiO (McKemmish et al 2019, and SH (Zahnle et al 2009;Yurchenko et al 2018).…”

The ExoMol Atlas of Molecular Opacities

“…Cross sections for alkaline earth monohydrides MgH and CaH from the Yadin ExoMol line lists[51] and NS from the SNaSH line list[74].…”