Compensation effect in the dissociation of anharmonic oscillators: A model for catalysis

Abstract

The differential form of the master equation for an anharmonic oscillator is solved in a steady-state approximation to derive an expression for the rate constant for dissociation. A small increase of the anharmonicity parameter causes a decrease of activation energy and thus a very large increase in the rate constant. The energy of activation is nearly linear with the logarithm of the preexponential when the magnitude of anharmonicity varies. This compensation effect, along with the sensitivity of the rate constant to anharmonicity, suggests a relationship to catalyzed dissociation.