After assuming that the transport of molecules between phases at thermal equilibrium results primarily from single molecular events, the expression for the rate of molecular transport between phases is developed by using a first order perturbation analysis of the Schrooinger equation and the Boltzmann definition of entropy. This leads to an Einstein-type relation with the constant of proportionality being the average rate of exchange between microscopic states of different molecular distributions. A hypothesis is introduced which leads to the conclusion that this exchange rate is unchanged as the system moves through the molecular distributions leading to equilibrium, and to it being equal to the molecular rate of exchange between phases in the final equilibrium state. This allows a complete expression for the rate of molecular transport between phases to be developed. The validity of the hypothesis can be examined by comparing the predictions that follow from the derived rate expressions with the available experimental data. This comparison is reported in subsequent parts of this work.

The statistical rate theory approach is used to derive the expression for the rate of adsorption of a nondissociating gas on a solid surface. By comparing the predicted adsorption with the available experimental results, one of the central assumptions in the statistical rate theory can be examined. On the basis of these experimental results, with which the theoretical predictions are found to be in close agreement, the assumption would appear to be valid. By being in close agreement with the experimental results throughout the experimental period, the adsorption rate expression derived from the statistical rate theory is an improvement over the presently available theories.

The statistical rate theory approach is used to derive the expression for the rate at which a diatomic gas dissociatively adsorbs on a solid surface. By comparing the predictions with available experimental evidence it is possible to examine one of the central assumptions in the statistical rate theory. The predictions were found to be in close agreement with two independent sets of experimental results; thus giving support to the basic assumption of the statistical rate theory. The close agreement extended throughout the experimental period; thereby making this approach an improvement over the presently available theories.

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