Electronic stress tensor description of chemical bonds using nonclassical bond order concept.

The stress tensors are used widely for description of internal forces of matter. For some time it is also applied in quantum theory in studies of molecular properties in chemical systems. Electronic stress tensors measure effects caused by internal forces acting on electrons in molecules and particularly those between bonded atoms. Utilized here stress tensor originated bond orders express bond strengths in terms of these internal forces. The unique concept of energy density and electronic chemical potential based bond orders gives natural evaluation of interaction strength compared with classical definition, considering delocalized nature of electrons. In addition to other causes, the relation to electronic energy may be used to predict relative stabilities of geometrical isomers or even conformers.