Pi-Electron Structure of Butadiene

Abstract

The spectrum and structure of butadiene have been considered by application of several nonempirical methods to the problem of the energy levels of the π‐electron system. Six spatial configurations of the nuclei have been treated, of which three correspond to the trans‐ form of the molecule and three, cis. The methods used include the use of antisymmetrized molecular orbitals with and without configuration interaction, electron‐pair bonds, a model based on two neighboring vinyl radicals, and the method of atoms in molecules as applied to the preceding techniques. A comparison of the results given by the different theories permits an evaluation of the theories, at least in the case of unsaturation electrons.