Reactive Collisions

Abstract

In this chapter, the application of the Schur–Weyl theorem to reactive collisions is discussed. In particular, reactions involving hydrogen are discussed. The most famous among them is possibly the $\mathrm{{H_3^++H_2}}$ reaction, which forms an intermediate $\mathrm{{H_5^+}}$ complex, which subsequently dissociates again. The symmetry properties of the intermediate complex are discussed and are found to be crucial for the selection rules for state-to-state transitions in this prototypical reactive collision. The respective symmetry properties are results from the potential energy surface of the full system. In addition to selection rules, we also discuss statistical properties of the state-to-state transitions in these reactions. The most important result of the calculations is actually the possibility to gain insights into the intermediate symmetry properties from experiments on the initial and final states of the reactants.