Unimolecular reactions in a spherically symmetric potential. II. Some tractable potentials

Collision cross sections derived from a long-range potential can be made more realistic through the addition of a short-range component. It is shown how this can be achieved with no loss of simplicity, and in agreement with experiment. Upon addition of a Coulombic term, improved expressions for ion–electron neutralization and thermionic emission are then obtained. These developments permit the transition between the small and large molecule regimes to be followed explicitly.