The present paper gives an elaborate theoretical description of a newmolecular charge transport mechanism applying to a single molecule trappedbetween two macroscopic electrodes in a solid state device. It is shown by aHubbard type model of the electronic and electrostatic interactions, that theclose proximity of metal electrodes may allow electrons to tunnel from theelectrode directly into a very localized image charge stabilized states on themolecule. Due to this mechanism, an exceptionally large number of redox statesmay be visited within an energy scale which would normally not allow themolecular HOMO-LUMO gap to be transversed. With a reasonable set of parameters,a good fit to recent experimental values may be obtained. The theoretical modelis furthermore used to search for the physical boundaries of this effect, andit is found that a rather narrow geometrical space is available for the newmechanism to be effective: In the specific case of oligophenylenevinylenemolecules recently explored in such devices several atoms in the terminalbenzene rings need to be at van der Waal's distance to the electrode in orderfor the mechanism to be effective. The model predicts, that chemisorption ofthe terminal benzene rings too gold electrodes will impede the image chargeeffect very significantly because the molecule is pushed away from theelectrode by the covalent thiol-gold bond.
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