Atomistic simulations of molecule formation and decomposition: from astrophysics to atmospheric chemistry

Atomistic simulations, with their increasing accuracy and predictive capabilities, have become indispensable tools for understanding molecular behavior at the atomic level. Employing reactive molecular dynamic (MD) simulations with accurate interaction potentials offers valuable insights into both atmospheric and interstellar chemistry. This thesis explores the reaction dynamics of small molecules in gas and condensed phases under controlled conditions.
In the gas phase, photoinduced dynamics of syn-acetaldehyde oxide Criegee intermediate leading to the formation of vinoxy and hydroxyl (OH) radicals, as well as glycolaldehyde is explored. Molecular dynamics simulations are performed, utilizing classical force fields and neural network based potential energy surfaces at the MP2 and CASPT2 levels of theory. By comparing the computed final OH translational
and rotational state distributions with experimental data, the O–O bond dissociation energy (