STRUCTURAL DISTORTIONS AND GAP STATES IN CONJUGATED POLYMERS

We present a simple scheme that allows for accurate estimates of the e nergies of orbitals induced by structural defects like solitons and po larons in conjugated polymers. The scheme works within a single-partic le framework and by considering solely the band structures of periodic , defect-free polymer chains. These latter may be obtained using param eter-free computational methods. We illustrate the scheme on four diff erent systems whereby we reproduce well-known results (trans polyacety lene), explain less well-known results (polycarbonitrile), demonstrate that correlation effects may not have to be invoked in order to expla in experimental findings (polythiophene), and present an alternative i nterpretation of experimental results (Pt-polyyne).