Hartree-Fock calculations for the electronic and lattice structures in heavily sodium doped polyacetylene

• Published in: Synthetic metals Vol. 85; no. 1; pp. 1061 - 1064
• Main Authors: Yamashiro, A., Ikawa, A., Fukutome, H.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 15.03.1997; Amsterdam Elsevier Science; New York, NY
• Subjects: Applied sciences; Electrical, magnetic and optical properties; Electron density; Exact sciences and technology; excitation spectra calculations; Metal-insulator phase transitions; Organic polymers; Physicochemistry of polymers; Polyacetyiene and derivatives; Properties and characterization; Semi-empirical models and model calculations; excitation spectra calculations; Semi-empirical models and model calculations; Electron density; Polyacetyiene and derivatives; Metal-insulator phase transitions; Hartree Fock model; Theoretical study; Coulomb interaction; Modeling; Acetylene polymer; Electronic structure; Metal insulator transition; Sodium; Doped polymer; Excitation spectrum; Electrical conductor; Lattice structure
• ISSN: 0379-6779; 1879-3290
• DOI: 10.1016/S0379-6779(97)80150-6

We evaluated 3D interactions in highly Na-doped polyacetylene, (CH) x, reasonably based on the structure reported in an X ray experiment. Interchain transfers (ICTs) via dopants estimated quantum chemically are found to reach up to 0.93 eV and spread over five sites on each adjacent chain at doping concentration, 11.1%, Screened Coulomb interactions are evaluated as Thomas-Fermi potential for quasi ID conductors numerically, 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 geometry optimization is soliton lattices out-of-phase ordered. The gap little depends on chain length and is extrapolated to 1.3eV in infinite chain limit. So rather large ICT in itself cannot lead to metallic state in HF approximation, and electron correlation seems to be important.