by Amélie Godard Palluet, on

Presentation of the conference

The Days of "Modeling, Theory and Simulation" were organized in Rennes (held online at the last minute due to sanitary restrictions) from the 8th to the 9th of December 2021.

The aim of this conference was to gather the modelers of the chemical physics community. It was a great opportunity to encourage young researchers to present their work, and encourage collaborations between the researchers. It was co-organized by the Division de Chimie Physique and the Réseau Français de Chimie Théorique (RFCT).

A. Godard Palluet participated and presented her work during this conference.

Collisional excitation of CO2 by He: New potential energy surface and scattering calculations - A. Godard Palluet, F. Thibault, F. Lique

Elastic (blue) and quenching (black) cross sections for CO2 and He collisions at j = 10, 20, 24, 30 and 40 in al-Qady et al. [1] (dashed) and our (plain) study.

The CO2-He collisional system is of great interest for astrophysical application since it can be found in a large variety of astrophysical media.
It is also a good prototype for more complex CO2-bearing collisional system, and therefore, it was well studied during the last decades. However, collisional data appear to be very sensitive to potential energy surfaces, and thus it is of primary importance to provide a PES as accurate as possible.
In this talk, I will present our recent study of the astrophysically relevant CO2-He collisional system. A new 2D potential energy surface was calculated with the Coupled Cluster method and a complete basis set extrapolation. Its accuracy was tested through the comparison of bound states and pressure broadening coefficients with experimental data. Revised collisional data were provided in the 10 - 300 K temperature range and were then compared to previous ones, published as part of a CO2 super-rotor study.
These new data exhibit the high sensitivity of collisional data to the PES, and can lead to a revision of the CO2 abundance and thus, to the physical conditions in astrophysical media were CO2 is present.

[1] W. H. al-Qady, R. C. Forrey, B. H. Yang, P. C. Stancil, and N. Balakrishnan, Physical Review A, 84, 054701 (2011)