A phase-space method for arbitrary bimolecular gas-phase reactions: Theoretical description

A theoretical model for the. calculation of rate constants for arbitrary bi molecular gas-phase reactions was developed. The method is based on the pha se-space statistical method developed by Light and co-workers [1 - 6]. In t he present article this method is extended to arbitrary molecular systems. The new method requires knowledge of the molecular properties in the reacti on and products channels of the chemical system. The properties are the vib rational frequencies, moments of inertia,,and potential energy for the inte racting species in their ground state equilibrium configuration. Furthermor e, we have to calculate either the energy barrier or the long-range potenti al for the chemical system (if the reaction channel does not have an energy barrier). The usefulness of the method is that it can be applied to all bi molecular reactions, trimolecular reactions, and even reactions of higher o rders. Therefore, it can be applied to cases where rate constants of comple x chemical reactions are required, but reliable laboratory measurements or other means to estimate rate parameters are not yet possible. Even if spect roscopic data are not available for the reactants and products, it is possi ble to use electronic structure theory to calculate the required data. (C) 2001 John Wiley & Sons, Inc.