The Orbital Correction Method

Abstract

It may be helpful at the outset to state briefly the method and the findings which we are to discuss. The orbital correction method is an approximate scheme for computing the total energy of molecules as a function of the arrangement of the constituent atoms. It is based upon a self-consistent-field treatment of the electron-electron interaction and an expansion technique analogous to perturbation theory. The expansion parameter in this case is the difference between the true one-electron state and an assumed starting state, which is essentially a linear combination of atomic orbitals. The simplification allowed by this expansion permits the treatment of arbitrarily large systems and gives a simple framework for the treatment of all properties of molecular systems. Preliminary application to the central hydrides illustrates the fact that many properties can be meaningfully treated in zero order (no orbital correction), while the inclusion of the orbital correction is absolutely essential in others.