Communication Dans Un Congrès Année : 2025

Seminar: State-to-state molecular collisions for astrophysics: towards increasing molecular complexity

S. Demes

Résumé

Recent advances in observational tools that are supported by state-of-the-art theoretical and experimental laboratory techniques, allow a more accurate determination of the composition and structure of matter in space. This has led to a recent surge in the number of new species observed in interstellar molecular clouds, confirming the presence of more than 330 types of molecules in such environments to date, where there is a growing trend towards the detection of complex organic molecules (COMs), including polycyclic aromatic hydrocarbons. Such large chemical complexity are not only seen in interstellar molecular clouds, but also in planetary and cometary atmospheres, where some in-situ measurements have also been carried out. The proper understanding of the multi-scale processes in such complex environments requires in-depth knowledge at the molecular level however. This implies the development of new methods for the state-to-state study of molecular interactions in both reactive and inelastic collisions of key astronomical species, which are relevant for resampling real conditions in space. In my talk, I will briefly summarise our recent findings on the rotational excitation of large cyclic and other complex polyatomic species due to inelastic collisions with He or H2. In particular, the state-to-state cross sections and rate coefficients will be presented. I will also introduce a new machine learning technique designed for the automated identification of general propensity trends in collisional data. This new technique can extrapolate rate coefficients for higher temperatures and higher quantum states with reasonable accuracy for astrophysical applications. Finally, I will provide insights into my ongoing project, which aims to describe the rovibrationally resolved collisions of polyatomic species with some of the most abundant collision partners in space.

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Dates et versions

hal-05462187 , version 1 (16-01-2026)

Identifiants

  • HAL Id : hal-05462187 , version 1

Citer

S. Demes. Seminar: State-to-state molecular collisions for astrophysics: towards increasing molecular complexity. Invited Seminar, IPR, Univ Rennes, Nov 2025, Rennes, France. ⟨hal-05462187⟩
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