NEAR-RESONANT SCATTERING FROM NONSYMMETRIC DIMERS - APPLICATIONS TO SUBSTITUTED POLYANILINES

In this work we show that, beyond the prediction of the random dimer m odel [Wu and Phillips, Phys. Rev. Lett. 66, 1366 (1991)], it is possib le to have near resonant scattering from nonsymmetric dimers. It is sh own by direct density of states calculations as well as by a procedure similar to the random dimer model that protonated chains of alkyl-sub stituted polyanilines support extended electronic states at the Fermi energy when a disordered distribution of symmetric or asymmetric bipol arons is present. An extension of the random dimer model to include re sonant scattering by nonsymmetric dimers is proposed.