Room temperature line lists for CO₂ symmetric isotopologues with ab initio computed intensities

Remote sensing experiments require high-accuracy, preferably sub-percent, line intensities and in response to this need we present computed room temperature line lists for six symmetric isotopologues of carbon dioxide: ¹³C¹⁶O₂, ¹⁴C¹⁶O₂, ¹²C¹⁷O₂, ¹²C¹⁸O₂, ¹³C¹⁷O₂ and ¹³C¹⁸O₂, covering the range 0–8000 cm⁻¹. Our calculation scheme is based on variational nuclear motion calculations and on a reliability analysis of the generated line intensities. Rotation–vibration wavefunctions and energy levels are computed using the DVR3D software suite and a high quality semi-empirical potential energy surface (PES), followed by computation of intensities using an ab initio dipole moment surface (DMS). Four line lists are computed for each isotopologue to quantify sensitivity to minor distortions of the PES/DMS. Reliable lines are benchmarked against recent state-of-the-art measurements and against the HITRAN2012 database, supporting the claim that the majority of line intensities for strong bands are predicted with sub-percent accuracy. Accurate line positions are generated using an effective Hamiltonian. We recommend the use of these line lists for future remote sensing studies and their inclusion in databases. - Highlights: • Line lists presented for symmetric isotopologues of carbon dioxide. • Intensities are computed ab initio and line positions from the CDSD database. • Intensities are provided the ¹⁴C isotopologue.