Introduction of the electron repulsion into the molecular orbital wave function

Abstract

The total MO wave function of a π-electron system contains covalent, total ionic and mixed parts. Taking the electron repulsions explicitly into account, the individual contribution of the parts are revaluated. The ω technique of Streitwieser is critically discussed and reformulated, disinguishing between odd and even numbered ω-electron systems. ω=0·5 (instead of Streitwieser's ω=1·4) fits the experimental data of ethylene reasonably well. This improved ω technique is used for taking the electron repulsions into account. The new method is applied to ethylene, butadiene, benzene, hexatriene, the allyl cation, the allyl radical and the allyl anion. A substantial improvement of the total π electron energy is achieved.