Changes in the band structure of a simple polymer on lowering the translational symmetry

By combining the one-dimensional crystal orbitals of a simple polymer under the action of a perturbation which extends the repeating segment from one site to n sites a perturbation method allows the band structure of the new chain to be calculated. As well as estimating the band gaps to a fairly good agreement with the results of the direct method the present technique shows how specific gaps created by the symmetry-lowering will respond to the characteristics of the perturbations imposed.