Polar structures in the theory of conjugated molecules III. The energy levels of benzene

Abstract The energy levels of benzene are calculated from a basis consisting of the five non-polar structures and tw enty-four polar structures, using the method given in part II. The role of polar structures is discussed. The results include a suggested new assignment for the 2080 Å bands of A1g- E2g, instead of A1g-B1u as required by molecular orbital theory. An intense A1g- E1u transition is calculated at 7·9 eV instead of the observed 6·7 to 7·0 eV. The disagreement with molecular orbital theory, to be dealt with more fully in a later paper, is briefly discussed.