Conductivity in polyacetylene. II. Ab initio and tight-binding calculations of soliton structure and reorganization energy in ordered and disordered structures

摘要: Alkali-doped polyacetylene is considered as an electron-transfer system. To estimate the reorganization energy due to bond-length changes when electrons are added or subtracted, we applied (U)MP2 and CASSCF methods small systems of type H(CH)NH. The simple tight-binding (Huckel) model with bond-length-dependent resonance integrals has been same larger polyenes. bond lengths obtained via orders for various oxidation states. results agree very well ab initio experiments Odd-N even-N behave differently. In odd-N systems, a structural “soliton” exists in neutral molecule. An electron can be removed without change. chains, perfect alternation molecule, length accepted occur over about 20 carbon atoms. tends constant value (0.22 eV) chain increased. Soliton structure studied function out-of-plane torsional defects it found that additional localized primarily on segment odd number presence positively charged ions, attracted toward this charge positive solitons formed at some distance from perturbing ion. © 1996 John Wiley & Sons, Inc.