The role of ‘Excluded’ electronic charge in noncovalent interactions

Abstract

ABSTRACTOur focus is upon a noncovalent molecular complex after its formation. In earlier work, we determined the ‘impenetrable’ volumes of the molecules A and B in a series of bimolecular complexes. In this paper, we investigate the amount and distribution of electronic charge that is excluded from these impenetrable volumes in each complex. We show that the strength of the interaction correlates reasonably well with the amount of this excluded charge. In accordance with the Hellmann–Feynman theorem and Feynman’s analysis of ‘dispersion’ forces, the noncovalent bond between A and B can be understood as the Coulombic interaction between the impenetrable volumes and the excluded electronic charge.