Ab initio Calculations for Astrochemistry

TL;DR

This paper reviews how ab initio computational chemistry aids astrochemical research by providing data on molecular interactions, collisional processes, and spectroscopic parameters crucial for understanding interstellar medium phenomena.

Contribution

It highlights recent advances in quantum chemistry methods for modeling interstellar molecules, emphasizing the importance of accurate datasets for collisional and reactive processes.

Findings

Quantum chemistry improves modeling of interstellar molecular interactions.

Accurate potential energy surfaces are essential for rate coefficient estimation.

Computational spectroscopy supports space observations and data interpretation.

Abstract

Computational chemistry plays a relevant role in many astrochemical research fields, either by complementing experimental measurements or by deriving parameters difficult to be reproduced by laboratories. While the role of computational spectroscopy in assisting new observations in space is described, the core of the chapter is the investigation of the collisional radiative transfer and the bimolecular reactive processes occurring in the gas-phase conditions of the interstellar medium, using as a guide the contributions presented by the authors at the "Second Italian National Congress on Proto(-planetary) Astrochemistry", held in Trieste in September 2023. In particular, the need for accurate datasets of collisional coefficients to model molecular abundances will be discussed. Then, the role of quantum chemistry in the investigation of interstellar-relevant potential energy surfaces will be described, focusing on accurate thermodynamic quantities for the estimate of rate coefficients.