Rotational excitation of CO2 induced by He: New potential energy surface and scattering calculations

A Godard Palluet (1, 2) , Franck Thibault (1) , François Lique (1, 2)

1 IPR - Institut de Physique de Rennes
2 LOMC - Laboratoire Ondes et Milieux Complexes

The CO2 molecule is of great interest for astrophysical studies since it can be found in a large variety of astrophysical media where it interacts with the dominant neutral species, such as He, H2, or H2O. The CO2-He collisional system was intensively studied over the last two decades. However, collisional data appear to be very sensitive to the potential energy surface (PES) quality. Thus, we provide, in this study, a new PES of the CO2-He van der Waals complex calculated with the coupled-cluster method and a complete basis set extrapolation in order to provide rotational rate coefficients that are as accurate as possible. The PES accuracy was tested through the calculations of bound state transition frequencies and pressure broadening coefficients that were compared to experimental data. An excellent agreement was globally found. Then, revised collisional data were provided for the 10-300 K temperature range. Rate coefficients were compared to previously computed ones and are found to be up to 50% greater than previously provided ones. These differences can induce non-negligible consequences for the modeling of CO2 abundance in astrophysical media. © 2022 Author(s).

Mots clés: Rate coefficients; Potential-energy surfaces; Neutral species; Coupled clusters methods; Complete basis sets; Collisional system; Collisional; Van der Waals forces; Quantum chemistry; Potential energy surfaces; Potential energy; Numerical methods; Molecular physics; Carbon dioxide; Rotational excitation; Scattering calculations; Van der Waals complex; Astrophysics; Quantum dynamics; Atomic and molecular collisions

Domaines: Physique [physics]

A Godard Palluet, Franck Thibault, François Lique. Rotational excitation of CO2 induced by He: New potential energy surface and scattering calculations. Journal of Chemical Physics, 2022, 156 (10), pp.104303. ⟨10.1063/5.0085094⟩. ⟨hal-03632769⟩