2020MNRAS.493.1531C

A new ro-vibrational line list for the ground electronic state of the main isotopologue ofacetylene,¹²C₂H², is computed as part of the ExoMol project. The aCeTY line list coversthe transition wavenumbers up to 10 000 cm^–1(λ>1µm), with lower and upper energylevels up to 12 000 and 22 000 cm^–1 considered, respectively. The calculations are performedup to a maximum value for the vibrational angular momentum,K_max=L_max=16, andmaximum rotational angular momentum,J=99. Higher values ofJwere not within thespecified wavenumber window. The aCeTY line list is considered to be complete up to2200 K, making it suitable for use in characterizing high-temperature exoplanet or cool stellaratmospheres. Einstein-A coefficients, which can directly be used to calculate intensities ata particular temperature, are computed for 4.3 billion (4 347 381 911) transitions between5 million (5 160 803) energy levels. We make comparisons against other available data for12C2H2, and demonstrate this to be the most complete line list available. The line list isavailable in electronic form from the online CDS and ExoMol data bases.