Binding regions in polyatomic molecules

A justification of Berlin's theorem that concerns the binding force concept in diatomic molecules is presented based on the Hellmann–Feynman theorem and its electrostatic interpretations. The concepts of binding and the binding region first derived by Berlin for diatomic molecules are extended to polyatomic molecules; the virial of forces necessary to hold the nuclei in a molecule fixed is proved to be an exact description of the total binding effect in the molecule. The partition of molecular space into binding and antibinding regions based on the binding function, which is defined in this paper, is proposed for polyatomic molecules. The binding diagrams for some planar molecules are developed as simple applications of our theoretical considerations. © 1993 John Wiley & Sons, Inc.