Anion-cation induction coupling in organic superconductors

Within the framework of the valence bond/Hartree-Fock (VB/HF) formalism, [C astet , J. Phys. I (France) 6, 583 (1996); L. Ducasse , Synth. Metals 85, 1 627 (1997); F. Castet , Chem. Phys. 232, 37 (1998); Synth. Metals 103, 1799 (1999)] anion-cation induction interactions are evaluated in organic super conductors derived from the Bechgaard salts. The calculation scheme is base d on an extension of the VB/HF model, so as to incorporate the effect of th e distinct anion polarization states in the calculation of the VB Hamiltoni an matrix elements. The induction mechanism involves a charge displacement on the counteranions in the electrostatic field of adjacent positively char ged organic molecules. Anion-cation interactions are calculated for the bet a-BEDTTTF2I3 structure [A. J. Schultz , J. Am. Chem Soc. 108, 7853 (1986)], which involves highly polarizable anions. (C) 2000 American Institute of P hysics. [S0021-9606(00)30523-2].