The Transmission Coefficient in the Theory of Absolute Reaction Rates

Abstract

The activated complex theory of reaction rates is discussed critically. The transmission coefficients for a number of idealized energy surfaces have been computed quantum mechanically. It appears that curvature of the reaction path may introduce activation energy in addition to that caused by constriction and elevation of the energy valley. Except at low temperatures, this additional activation energy is almost negligible. However, it may contribute to the separation of isotopes, where small differences in activation energy are important. For systems in thermal equilibrium at room temperatures and above, the average quantum mechanical transmission coefficient is found to differ insignificantly from that calculated by classical mechanics.