Molecular Orbital Study of Nonadditive Substituent Effects

摘要

It is shown that the singlehyphen;parameter molecular orbital models of substituent perturbations of the benzene ring require that the charge density changes be odd, and the bond orders and polarizabilities be even functions of the perturbation parameters. This behavior excludes the possibility of a cross term in the MO description of those properties of disubstituted benzenes which are proportional to the pihyphen;electron charge densities.