The Rates of Second-Order Gas Reactions

It has been shown that the most accurate existing measurements of the rates of second-order gas reactions show deviations from pure exponential temperature dependence, which can be empirically represented by a linear increase of the energy of activation with temperature. It is pointed out that this requires the chance of reaction to increase with the energy of the collision in a continuous fashion. Assuming a particular form for this variation, a theory is worked out which predicts that this linear increase shall fail at temperatures only slightly higher than those yet reached in the hydrogen iodide decomposition. There is reason to believe that the numerical results of this theory are substantially correct, even though the detailed assumptions are doubtless far from right.