A hybrid approach to generating diatomic line lists for high resolution studies of exoplanets and other hot astronomical objects: updates to ExoMol MgO, TiO, and VO line lists

• Published in: RAS techniques and instruments 2024-01, Vol.3 (1), p.565-583
• Main Authors: McKemmish, Laura K, Bowesman, Charles A, Kefala, Kyriaki, Perri, Armando N, Syme, Anna-Maree, Yurchenko, Sergei N, Tennyson, Jonathan
• Format: Article
• Language: English
• ISSN: 2752-8200; 2752-8200
• DOI: 10.1093/rasti/rzae037

The best molecular line lists for astrophysical applications today require both high accuracy of line positions for strong lines as well as high overall completeness. The former is required to enable, for example, molecular detection in high-resolution cross-correlation observations of exoplanets, while completeness is required for accurate spectroscopic and radiative properties over broad temperature and spectral ranges. The use of empirical energies generated with the marvel procedure is a standard way to improve accuracy; here we explore methods of extending the use of these levels using predicted shifts and isotopologue extrapolation, as well as augmenting the levels from other sources such as effective Hamiltonian studies. These methods are used to update ExoMol line lists for the main $^{24}$Mg$^{16}$O and $^{48}$Ti$^{16}$O isotopologues, as well as for $^{24}$Mg$^{17}$O, $^{24}$Mg$^{18}$O, $^{25}$Mg$^{16}$O, $^{26}$Mg$^{16}$O, $^{46}$Ti$^{16}$O, $^{47}$Ti$^{16}$O, $^{49}$Ti$^{16}$O, and $^{50}$Ti$^{16}$O; new marvel results for $^{51}$V$^{16}$O are also presented.