Comparison of the Classical Theories of Unimolecular Reactions. II. A Model Calculation

A formulation due to Slater is used to determine the first-order rate constant at all pressures for the dissociation of a linear, symmetric, triatomic molecule with Morse bond-stretching potentials. The gap distribution is examined with the aid of numerical calculations carried out on a digital computer. It is found that the gap distribution is adequately represented by a gamma distribution, which approaches a random distribution as the energy approaches E0. The Giddings—Eyring theory is in excellent agreement with the ``exact'' result. Harmonic approximation theories are in poor agreement.