On the Mechanism of Low-Temperature Termolecular Atomic Recombination

Abstract

A simple theory of gas‐phase termolecular atomic recombination kinetics is presented which treats the bound‐complex (BC) mechanism in a fashion which parallels the Roberts, Bernstein, and Curtiss resonance theory of the energy‐transfer (ET) mechanism. The ET rate constant has a low temperature maximum, but the BC rate constant does not. The contributions of the two mechanisms to the low‐temperature recombination of hydrogen atoms, with He, Ar, and H₂ as third bodies, are estimated and compared. The presence (absence) of a low‐temperature maximum in the observable total rate constant is determined by absence (presence) of bound vibrational levels of the hydrogen‐third body van der Waals dimer. Hence, experimental studies of these reactions could yield valuable information about the interatomic potentials.