Scattering Experiments and Classical Theory of Atom–Atom Scattering

The chapter starts with a brief review of the crossed molecular beam apparatus that created a breakthrough in the study of reactive molecular collisions in 1972 and was, in large part, responsible for the award of a Nobel Prize in 1986. The remainder of the chapter discusses atom–atom collisions using classical mechanics. The collision of two hard spheres is first considered followed by collisions of two atoms interacting through a typical potential. This discussion introduces many important concepts, such as impact parameter, integral and differential cross sections and glory and rainbow scattering. It ends with a discussion of Newton diagrams and the relationship between laboratory and center-of-mass reference frames.