Reactions Involving Hydrogen Molecules and Atoms

Abstract

The criticisms of Coolidge and James of activation energy calculations are discussed. It is pointed out that their criticisms of the original London proposal do not apply to the semi‐empirical method which in its present form has little more than a formal resemblance to the original scheme. Until a satisfactory quantum‐mechanical derivation of the semi‐empirical method is provided, it must depend for acceptance on its usefulness and the fact that it is a reasonable interpolation formula for calculating the energies of polyatomic molecules from diatomic ones. The best surface for three hydrogen atoms is constructed and from it the rates of all the possible hydrogen‐deuterium reactions are calculated by means of the general theory of absolute rates, these rates are found to be in excellent agreement with the experimental values. The transmission coefficient for reactions on this surface is investigated. Diagrams showing the angular dependence of the potential energy for an H and for a Cl atom approaching a hydrogen molecule are given.