| Abstract
| - We present a systematic theoretical investigation of the interaction of an organic molecule with gold andpalladium electrodes. We show that the chemical nature of the electrode elicits significant geometrical changesin the molecule. These changes, which are characteristic of the electrode atomic species and the interfacegeometry, are shown to occur at distances as great as 10 Å from the interface, leading to a significantmodification of the inherent electronic properties of the molecule. In certain interface geometries, the highestoccupied molecular orbital (HOMO) of the palladium-contacted molecule exhibits enhanced chargedelocalization at the center of the molecule, compared to gold. Also, the energy gap between the conductancepeak of the lowest unoccupied molecular orbital (LUMO) and the Fermi level is smaller for the case of thepalladium electrode, thereby giving rise to a higher current level at a given bias than the gold-contactedmolecule. These results indicate that an optimal choice of the atomic species and contact geometry couldlead to significantly enhanced conductance of molecular devices and could serve as a viable alternative tomolecular derivatization.
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