Studies of the Interaction between Stable Molecules and Atoms. I. A Molecular Orbital Theory of the Activation Energy between Molecules and Atoms

Abstract

The molecular orbital method of calculation is applied to the interaction between closed-shell species; the results discussed in this paper and presented in the following papers of this series indicate that this method will yield quantitative results for energies of a system as function of internuclear parameters if one is interested in the differences in energy for two different geometric ground state configurations of the system. The molecular orbitals are used as a basis of constructing correlation diagrams for predicting mechanisms and calculating activation energies for chemical reactions. The orbitals of the reactants and products are correlated with the orbitals of a state defined as the ambivalent complex. The low-lying excited states of the interacting molecules seem to be of importance in determining the activation energy of a chemical reaction. Considerable qualitative insight into the activation process is gained by this method; the relative values of the activation energies for the interaction between two closed-shell molecules, a molecule and a radical, and two radicals are predicted in agreement with experiment.