Figure . An idealised potential energy surface (PES) for an SN2 reaction, reproduced with permission from E. H. E. Farrar. The TS corresponds to the highest energy point along a reaction pathway, marking the conversion of reactants to products, and is pivotal to understanding chemical reactions and their mechanisms. The energy difference between the TS and the reactant state corresponds to the activation energy barrier, which provides valuable information about the probability of a reaction occurring at a given temperature. Furthermore, the TS offers insights into the fundamental reaction mechanism by revealing the orientation in which reactants interact. The energy of the TS also enables the calculation of key kinetic and thermodynamic reaction properties. Hence, the correct TS can provide valuable insights into the chemistry at hand, but obtaining the TS is a difficult task.