Benchmark Rovibrational Linelists and Einstein A-coefficients for the Primordial Molecules and Isotopologues

Abstract

Complete benchmark rovibrational energy linelists calculated for the primordial polar molecules of the universe, namely HD + , HD, and the HeH + isotopologues, with accuracy up to 10 −2 cm −1 for low-lying states, are presented. To allow for these calculations to be performed, new high-accuracy potential energy curves, which include the diagonal Born-Oppenheimer adiabatic corrections and the leading relativistic corrections, are determined. Also, a new approach for calculating non-adiabatic corrections involving an effective vibrational nuclear mass obtained based on the atoms-in-molecules theory is employed. The vibrational and rotational masses are taken as being different and dependent on the nuclear distance. Accurate dipole moment curves are calculated and used to generate lists of Einstein A-coefficients. The energy linelists and the sets of Einstein A-coefficients for HD are upgrades of previous calculations including quasibound states, while for HD + and HeH + and its isotopologues the present results represent significant improvement over the previous calculations. The results obtained here suggest that, with the inclusion of the non-adiabatic corrections, the accuracy limit at least for low-lying states might have been reached. Thus, further progress should involve accounting for even smaller effects such as the quantumelectrodynamics corrections. The present results represent the state-of-the-art of theoretical spectroscopy of the primordial polar molecules.

The 2020 release of the ExoMol database: Molecular line lists for exoplanet and other hot atmospheres

“…One and two electron diatomics are important primordial species and may well play a role elsewhere. Recently Amaral et al [166] created new line lists using high level ab initio procedures. These line lists have been included in the database with the name ADSJAAM.…”

Impact of photochemical hazes and gases on exoplanet atmospheric thermal structure

“…At longer wavelengths opacities are calculated based on the correlated-k method (Lacis & Oinas 1991) utilising molecular line lists from the Exomol, Theorets, and MoLLIST groups. These include opacities for H2O (Polyansky et al 2018), CO (Li et al 2015), CH4 (Rey et al 2017), NH3 (Coles et al 2019), H2S (Azzam et al 2016), CO2 Rothman et al (2010), HCN (Barber et al 2013), C2H2 (Chubb et al 2020, TiO (an updated in 2012 version of Plez 1998), VO (McKemmish et al 2016), He + 3 (Mizus et al 2017) and HeH + (Amaral et al 2019). In the current simulations we do not treat condensation and cloud formation thus do not include opacities for silicate species.…”

ExoMol line lists – XL. Rovibrational molecular line list for the hydronium ion (H3O+)

“…ExoMol project originally concentrated on providing line lists for neutral molecules. At present the database contains line lists for a number of ions of (possible) importance for studies of the early Universe, namely HD + (Amaral et al 2019), HeH + (Engel et al 2005;Amaral et al 2019), LiH + (Coppola et al 2011), and H + 3 Mizus et al (2017). For ions important in (exo-)planetary atmosphere the database so far only contains line lists for H + 3 and OH + (Bernath 2020; Wang et al 2020).…”