Unimolecular Rates Due to Multiple Critical Oscillators

Abstract

In the first part it is shown that Kassel's quantum model differs appreciably from the classical model in the description of the unimolecular pressure falloff behavior. In the second part the quantum model is extended to encompass dissociation by the accumulation of energy in several critical oscillators. The specific rate constant for molecules with energy E is developed along with the limiting high and low pressure rate constants, as well as the concomitant activation energy expressions. The approximations of the classical theory are indicated by comparisons of the relevant quantum and classical formulations.