The electronic structure of conjugated systems. VI

Abstract This part reconsiders the previously neglected non-orthogonality of atomic orbitals. New generalized definitions of fractional bond order and charge distribution are introduced, and it is shown that under certain conditions, which are satisfied by most conjugated hydro-carbons, the overlap factor is completely irrelevant in calculating bond orders and charges. For heteromolecules this is not the case, and substantial changes may sometimes be made by its inclusion. The various polarizability coefficients introduced in earlier papers are always affected, but numerical results suggest that these changes are not very large.