Spindle structure of the stress tensor of chemical bond

Covalent bond describes electron pairing in between a pair of atoms and molecules. In the current paper, the space is partitioned in mutually disjoint regions by using new concept of the electronic drop region RD, atmosphere region RA, and the interface S [Tachibana, A. J Chem Phys 2001, 115, 3497]. The covalent bond formation is then characterized by a new concept of the spindle structure. The spindle structure is a geometrical object of a region where principal electronic stress is positive along a line of principal axis of the electronic stress that connects a pair of the R(D)s of atoms and molecules. Using virial theorem of the rigged quantum electrodynamics (QED), a new energy density partitioning scheme is obtained using the kinetic energy densities. In the current paper, a concise judgment condition to identify the given unknown locality as a spindle structure of a covalent bond is formulated in the frame of the nonrelativistic limit of QED. A physical interpretation of the local dynamics of the chosen spindle structure is also guaranteed at the same time as the judgment of the generalized chemical reactivity in terms of the physical quantum mechanical law that is hierarchic and localized. A general frame to elucidate a feature structure and the character of the classification concerning the expression of the internal symmetry of chemical reaction to the chosen spindle structure class is given in a unified way. (C) 2004 Wiley Periodicals, Inc.