The Chemical Bond in Molecular Quantum Mechanics

Abstract

It is postulated that a properly antisymmetrized product function over geminals (electron‐pair wave functions) is adequate for discussion of the principal chemical properties of molecules. By application of the virial theorem it is shown that such a wave function has both of the properties essential to the bond‐energy concept; namely (a) the energy of a molecule is the sum of the energies of its individual bonds and (b) the bond energies are invariant from one molecule to another. Within the framework of this approximation, bond energies become identified in magnitude with the kinetic energies associated with the respective geminals. The concepts are sufficiently general to include both localized and nonlocalized bonds, unshared electron pairs, odd electrons, and states of various multiplicities.