Collision Mechanics in Crossed Maxwellian Molecular Beams

A general treatment of the mechanics of collision between two Maxwellian molecular beams is described. Expressions are obtained for the distribution in collision energy, for the elastic and reactive collision rates, and for the angular distribution of the center of mass vectors for beams colliding at any angle. The treatment can accommodate any reaction cross section which can be expressed as a step function multiplied by a linear combination of powers of the relative energy. The recoil momentum which affects the product distribution in the laboratory system is discussed, and the treatment is applied to some experimental data on the reaction of K with HBr.