CONFORMATIONAL AND ELECTRONIC-PROPERTIES OF FLEXIBLE CONDUCTING POLYMER-CHAINS

The conformational and electronic properties of flexible conducting po lymer chains are investigated. As a starting point a general Hamiltoni an for conjugated flexible chains is presented. The pi electrons are d escribed in terms of a Hubbard model confined to the chain modeled by (random) walks. One main result is that electronic degrees greatly aff ect the conformation which is shown explicitly for a melt of conjugate d polymers. The presence of electrons leads to a significant stiffenin g (rigidification) of the chains, i.e., the effective persistence leng th is increased. The other important point is the effect of the confor mation of the chain on the electron-electron interaction. This leads t o a weak disorder-induced localization of the electrons. An effective pair potential is derived using Feynman-graph techniques.