T. Yamasaki et al., Correlation analysis of chemical bonds (CACB) II: Quantum mechanical operators for classical chemical concepts, J PHYS CH A, 104(11), 2000, pp. 2221-2229
We apply correlation analysis of chemical bonds (CACB) to simple organic re
action paths. CACB, an operator based formalism for analyzing the electroni
c structure for molecule, clarifies how bond exchange processes relate to c
hanges in covalent bond orders and bond interaction coefficients. For singl
e bond-exchange processes, the bonds correlation typically is negative for
interchanging bonds. For two bond-exchange processes, this coefficient can
be either negative or slightly positive near zero, reflecting the nature of
the bond exchange process. The simplest formalism can, sometimes, lead to
unphysical values for the atomic valence and the bonds correlation coeffici
ents. We analyzed the origin of this behavior and attributed it to the non-
Hermitian property of the operator. We show how to avoid this problem by sy
mmetrizing the operator through use of orthogonal atomic orbitals.