ExoMol line lists – XLIV. Infrared and ultraviolet line list for silicon monoxide (28Si16O)

Abstract

A new silicon monoxide (28Si16O) line list covering infrared, visible and ultraviolet regions called SiOUVenIR is presented. This line list extends the infrared EBJT ExoMol line list by including vibronic transitions to the A 1Π and E 1Σ+ electronic states. Strong perturbations to the A 1Π band system are accurately modelled through the treatment of 6 dark electronic states: C 1Σ−, D 1Δ, a 3Σ+, b 3Π, e 3Σ− and d 3Δ. Along with the X 1Σ+ ground state, these 9 electronic states were used to build a comprehensive spectroscopic model of SiO using a combination of empirical and ab initio curves, including the potential energy (PE), spin-orbit (SO), electronic angular momentum (EAM) and (transition) dipole moment curves. The ab initio PE and coupling curves, computed at the multireference configuration interaction (MRCI) level of theory, were refined by fitting their analytical representations to 2617 experimentally derived SiO energy levels determined from 97 vibronic bands belonging to the X–X, E–X and A–X electronic systems through the MARVEL procedure. 112 observed forbidden transitions from the C–X, D–X, e–X, and d–X bands were assigned using our predictions, and these could be fed back into the MARVEL procedure. The SiOUVenIR line list was computed using published ab initio transition dipole moments for the E–X and A–X bands; the line list is suitable for temperatures up to 10 000 K and for wavelengths longer than 140 nm. SiOUVenIR is available from www.exomol.com and the CDS database.

Sunbathing under white light -- 3D modelling of brown dwarf - white dwarf atmospheres with strong UV irradiation

“…Their results suggest that the downward mixing in SDSS 1411B is weaker compared to main sequence irradiated brown dwarfs. Zhou et al (2021) performed GCM models of WD0137B and EPIC 2122B to accompany HST WFC3 data analysis, similar to the Tan & Showman (2020) set-up. This used a simplified semi-grey approach with two UV-Optical shortwaves channels tuned to the 1D models of Lothringer & Casewell (2020).…”

Five Key Exoplanet Questions Answered via the Analysis of 25 Hot-Jupiter Atmospheres in Eclipse

“…2 O(Barton et al 2017;Polyansky et al 2018), CH 4(Hill et al 2013;Yurchenko & Tennyson 2014), CO(Li et al 2015), CO 2(Yurchenko et al 2020), TiO (McKemmish et al 2019), VO (McKemmish et al 2016), FeH (Bernath 2020), and H -(John 1988; Edwards et al 2020) depending on the model considered. In the chemical equilibrium runs, additional molecules are considered: HCN (Barber et al 2013), H 2 CO (Al-Refaie et al 2015), H 2 S (Azzam et al 2016), CN (Syme & McKemmish 2021), CP (Ram et al 2014; Bernath 2020; Qin et al 2021), C 2 H 2 (Chubb et al 2020b), C 2 H 4(Mant et al 2018), NH 3(Al Derzi et al 2015;Coles et al 2019), MgO(Li et al 2019), AlO(Patrascu et al 2015;Bowesman et al 2021), SiO(Barton et al 2013;Yurchenko et al 2022), PH 3 (Sousa-Silva et al 2015, ScH…”

Dust formation in the outflows of catastrophically evaporating planets

“…For the gas opacity, we assume a fixed composition based upon Schaefer & Fegley (2009), as detailed in Appendix A. We include SiO, MgO, Fe, O, and Mg as opacity sources using the line-lists from ExoMol (Li et al 2019;Yurchenko et al 2021) and Kurucz (1992). We have assumed local thermodynamic equilibrium for the levelpopulations and take into account natural and Doppler broadening, but neglect pressure broadening due to the low pressures considered here ( 10 −6 bar).…”

“…Pressure-broadening is neglected due to the low pressures considered. We include SiO, MgO, Fe, O, and Mg as opacity sources using the line-lists from ExoMol (Li et al 2019;Yurchenko et al 2021) and Kurucz (1992). Other species present, such as O 2 and SiO 2 do not contribute significantly to the total opacity (e.g.…”