A review of applications of the concept of chemical fragmentation in the theory of molecular orbitals of large covalent systems is presented. The use of this concept makes it possible to vastly reduce the volume of computations. It is demonstrated that the use of standard molecular parameters, such as the topology or location and composition of the reaction center, substantially simplifies the construction of a reasonable initial wave function and, hence, the solution of the Schrödinger equation. Localized molecular orbitals provide a natural basis for fragmentation and can be extended to describe large building blocks of a covalent system. Systems in which chemical changes are localized on a few atoms, while the others play the role of an electrostatic perturbation can be divided into an active site and an environment; this procedure constitutes the basis of quantum mechanics-molecular mechanics hybrid methods. A complete quantum mechanical treatment of large covalent systems can be performed within the framework of the fragment self-consistent method developed over the past two decades in our laboratory.
|Number of pages||6|
|Journal||Russian Journal of Physical Chemistry A|
|Publication status||Published - Jan 1 2000|
ASJC Scopus subject areas
- Physical and Theoretical Chemistry