HARTREE-FOCK CALCULATIONS FOR THE ELECTRONIC AND LATTICE STRUCTURES IN HEAVILY SODIUM DOPED POLYACETYLENE

We evaluated 3D interactions in highly Na-doped polyacetylene, (CH)(x) , reasonably based on the structure reported in an X ray experiment. I nterchain transfers (ICTs) via dopants estimated Quantum chemically ar e found to reach up to 0.93 eV and spread over five sites on each adja cent chain at doping concentration, 11.1%. Screened Coulomb interactio ns are evaluated as Thomas-Fermi potential for quasi 1D conductors num erically, to estimate reasonable interchain Coulomb (ICC) and dopants' Coulomb (DC) potentials. As the intrachain Hamiltonian, SSH+extended Hubbard model is used. The Hartree-Fock (HF) ground state with geometr y optimization is soliton lattices out-of-phase ordered. The gap littl e depends on chain length and is extrapolated to 1.3eV in infinite cha in limit. So rather large ICT in itself cannot lead to metallic state in HF approximation, and electron correlation seems to be important.