Crossed-beam studies of reaction dynamics

This article reviews recent progress in our understanding of gas-phase neut ral reaction dynamics as made possible by improvements in the crossed molec ular beam scattering technique for measuring reactive differential cross se ctions. A selection of crossed-beam studies on systems that play a fundamen tal role in our basic understanding of reaction phenomena are discussed to illustrate the capabilities of the experimental method. The examples includ e benchmark atom-diatom abstraction and insertion reactions, and four-atom radical reactions for which state-to-state, state-resolved, or state-averag ed differential cross sections have recently been measured. The results are discussed in the light of the latest related theoretical developments rega rding the treatment of potential energy surfaces and the dynamics of the sy stems. Recent results on crossed-beam studies of chemically relevant reacti ons of carbon, nitrogen, and oxygen atoms are also reviewed, and the latest developments in the technique are noted.