Three-body recombination reactions, requiring three reactants to form the reaction product, are key to a multitude of relevant physical processes, spanning more than four orders of magnitude in temperature, from cryogenic environments to plasmas. However, despite their relevance, there is no general theoretical framework to deal with them. This project aims to develop a comprehensive theoretical framework for three-body recombination reactions, including atoms, molecules, and ions as reactants, with applications in cold chemistry, atmospheric chemistry (ozone formation), and plasma physics. Additionally, this project will focus on a new course designed to orient new students across departments on what a Physics degree can offer in the professional world. This project has three main objectives: (1) to develop a theoretical framework for three-body recombination reactions involving partners with internal degrees of freedom; (2) to apply semi-classical theory to three-body recombination reactions: hybrid ion-atom traps and plasma physics; and (3) to understand ozone formation in the stratosphere. To achieve these objectives, a novel semi-classical theory for three-body recombination reactions will be developed, based on a classical trajectory approach in hyperspherical coordinates. The results will be benchmarked against existing (but unexplained) experimental data in several systems of interest. Furthermore, the underlying potential energy surfaces required for evaluating t