M. Meneghetti, Direct evidence of a new type of electron-phonon interaction in charge transfer molecular conductors and superconductors, SYNTH METAL, 120(1-3), 2001, pp. 859-860
The modulation of the electron correlation term U of the Hubbard Hamiltonia
n by intramolecular normal mode of vibrations (U-vib interaction) is consid
ered for a two-site two-electron model. It is shown how this interaction pe
rturbs the Raman active modes and how these can be used for determining the
corresponding coupling constants. One finds that the C=C stretching mode o
f TMTXF (X=T, S) molecules strongly modulates the U interaction. This sugge
sts that a bipolaronic mechanism may be active for the pairing of electrons
in the superconductors based on this type of molecules.