FRAGMENTAL ANALYSIS OF ENERGIES OF ELECTRONIC-TRANSITION IN MONOSUBSTITUTED BENZENE-DERIVATIVES .1. A SINGLE CONFIGURATION APPROXIMATION

On the basis of the expression of the MO through fragment orbitals (FO) in monosubstituted benzene derivatives, the energies of the singlet electronic transitions in a single configuration (SC) approximation were decomposed into fragmental and interfragmental components. It was shown that the fragmental (phenyl) component is determined by the localization number (LN) of the MO and by transferable parameters - the corresponding values of SC transitions in benzene. As a result of changes in the LN in various molecules, both the fragmental (phenyl) component for various transitions and the interfragmental component change strongly. However, the expression of the MO through the FO makes it possible to carry out a sharp comparison of SC transitions in the parent (benzene) molecule and its substituted derivatives.