RESONANT SCATTERING THEORY OF ASSOCIATION REACTIONS AND UNIMOLECULAR DECOMPOSITION .I. A UNITED THEORY OF RADIATIVE AND COLLISIONAL RECOMBINATION

A complete quantum-mechanical theory of unimolecular kinetics and of predissociation is developed using a generalized version of Fano's theory of resonant scattering. An important feature of the theory is that it treats the irreversible couplings between the activated molecules and either the photon field (predissociation) or the inelastic collisions with bath molecules (unimolecular decomposition) by means of an optical potential, and leads to very concise and, certainly in the case of predissociation, exact results. The final form of the rate expressions resembles the Eyring Absolute Rate Theory (ART), with the important result that explicit theoretical expressions are given for the 'transmission coefficients' as a function of temperature and pressure, which in principle allows us to calculate the rates.