INTER-IMPURITY INTERACTION IN DOPED CONJUGATED POLYMERS - 2 IMPURITY PROBLEM AND DEPENDENCE ON IMPURITY-POTENTIAL FORMS

Effects of inter-impurity interaction in conjugated polymers are numerically investigated. The Su-Schrieffer-Heeger (SSH) hamiltonian is used for the polymer chain. There are two acceptor-type long-ranged impurities, with anisotropic dielectric constants and a screening factor. Direct inter-impurity repulsion is taken into account. Impurity arrangements as well as lattice and electron configurations are determined so as to minimize the total energy. Impurity clustering occurs when the range of the impurity potential is long enough. Impurities are isolated each other when the range becomes shorter. In order to look at how the clustering would be observed, optical absorption is calculated. There exists only one mid-gap absorption peak. This is the consequence of the strong impurity potential. © 1992, Taylor & Francis Group, LLC. All rights reserved.