Combined ab initio and density functional study on polaron to bipolaron transitions in oligophenyls and oligothiophenes

被引:49
作者
Irle, S
Lischka, H
机构
[1] Inst. F. Theor. Chem. Strahlenchemie, Universität Wien, A-1090 Wien
关键词
D O I
10.1063/1.474701
中图分类号
O64 [物理化学(理论化学)、化学物理学];
学科分类号
070304 ; 081704 ;
摘要
Ab initio self-consistent-field (SCF), two-configuration SCF (TCSCF), and density functional theory (DFT) calculations on the charge-transfer complexes of doubly Li/Cl-doped oligothiophenes and oligo(p-phenyls) and on respective charged systems without counterions have been carried out in order to study polaron to bipolaron transitions. Oligomer chains up to octamers and the ring structures cyclo-dodecathiophene and cyclo-dodeca(p-phenyl) have been investigated. Special attention is paid to the open-shell biradical character of two isolated polaronic defects. It is found that the TCSCF and the spin-unrestricted DFT methods can be successfully applied. A bipolaron structure is obtained when the doping atoms are located on neighboring rings and when there is one undoped ring separating the two doped ones. If there are two or more undoped rings in between a two-polaron configuration (biradical) is found. The bipolaron system is calculated to be more stable than the two-polaron case when counterions are taken into account. The stabilities are reversed if the bare, doubly-charged systems are considered. A theoretical estimate for the barrier height of the polaron to bipolaron transition is given using model reaction coordinates. (C) 1997 American Institute of Physics.
引用
收藏
页码:3021 / 3031
页数:11
相关论文
共 48 条
  • [1] ELECTRONIC-STRUCTURE CALCULATIONS ON WORKSTATION COMPUTERS - THE PROGRAM SYSTEM TURBOMOLE
    AHLRICHS, R
    BAR, M
    HASER, M
    HORN, H
    KOLMEL, C
    [J]. CHEMICAL PHYSICS LETTERS, 1989, 162 (03) : 165 - 169
  • [2] [Anonymous], MODERN THEORETICAL C
  • [3] [Anonymous], 1991, Conjugated Polymers: The Novel Science and Technology of Highly Conducting and Nonlinear Optically Active Material
  • [4] BAKER J, 1993, CHEM PHYS LETT, V216, P38
  • [5] DENSITY-FUNCTIONAL EXCHANGE-ENERGY APPROXIMATION WITH CORRECT ASYMPTOTIC-BEHAVIOR
    BECKE, AD
    [J]. PHYSICAL REVIEW A, 1988, 38 (06): : 3098 - 3100
  • [6] POLARONS, BIPOLARONS, AND SOLITONS IN CONDUCTING POLYMERS
    BREDAS, JL
    STREET, GB
    [J]. ACCOUNTS OF CHEMICAL RESEARCH, 1985, 18 (10) : 309 - 315
  • [7] HIGHLY CONDUCTING POLYPARAPHENYLENE, POLYPYRROLE, AND POLYTHIOPHENE CHAINS - AN ABINITIO STUDY OF THE GEOMETRY AND ELECTRONIC-STRUCTURE MODIFICATIONS UPON DOPING
    BREDAS, JL
    THEMANS, B
    FRIPIAT, JG
    ANDRE, JM
    CHANCE, RR
    [J]. PHYSICAL REVIEW B, 1984, 29 (12): : 6761 - 6773
  • [8] BREDAS JL, 1990, NATO ASI SERIES E, V182
  • [9] CONFINED SOLITON PAIRS (BIPOLARONS) IN POLYTHIOPHENE - INSITU MAGNETIC-RESONANCE MEASUREMENTS
    CHEN, J
    HEEGER, AJ
    WUDL, F
    [J]. SOLID STATE COMMUNICATIONS, 1986, 58 (04) : 251 - 257
  • [10] ROLE OF CHARGE-TRANSFER AND QUINONOID STRUCTURE IN THE RAMAN-SPECTRUM OF DOPED POLY(P-PHENYLENE)
    CUFF, LL
    CUI, CX
    KERTESZ, M
    [J]. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1994, 116 (20) : 9269 - 9274