ExoMol Line Lists -- LXII: Ro-Vibrational Energy Levels and Line-Strengths for the Propadienediylidene (C3) in its Ground Electronic State

2024/10/23 by A. E. Lynas-Gray, Lynas-Gray, A. E., O. L. Polyansky +7
Physics and Astronomy · Chemistry · #Advanced Chemical Physics Studies #Molecular Spectroscopy and Structure #Atomic and Molecular Physics

paper · pdf · doi:10.48550/arxiv.2410.18250

Abstract

Improved opacities are needed for modelling the atmospheres and evolution of cool carbon-rich stars and extra-solar planets; in particular, contributions made by the astrophysically important propadienediylidene (C₃) molecule need, at a minimum, to be determined using a line list which includes all significant transitions in the energy range of interest. We report variational calculations giving ro-vibrational energy levels and corresponding line-strengths for ¹²C₃, ¹²C¹³C¹²C and ¹²C¹²C¹³C. In the ¹²C₃ case we obtain 2166503 ro-vibrational state energies ≤ 20000 cm^-1 for the electronic X¹ Σ_g⁺ ground-state. Comparison with experiment indicates a maximum error of +/- 0.03 cm^-1 in calculated positions of lines involving an upper state energy \lesssim 4000 cm^-1. For lines with upper state energies \gtrsim 4000 cm^-1 to have comparable line-position accuracies, conical intersections would need to be accounted for in an adopted potential energy surface. Line lists and associated opacities are provided in the ExoMol Database http://www.exomol.com ).

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