Electron transport through molecular wire: effect of isomery

We report the electronic transport property of molecular wires by an ab inito molecular orbital theory on the basis of the first-principle density functional theory (DFT) and the non-equilibrium Green's function (NEGF) formalism. The wires consist of three kinds of isomer molecules (pyrimidine, pyrazine and pyridazine, shown in the first figure) which are attached to the atomic scale gold electrodes. Our calculation reveal: (1) the relative position of the double nitrogen atoms in the molecular rings can significantly affect the transport behavior due to change in the electronic structure of the molecule and (2) the conductance of pyrazine exhibits an ohmic character on a large range. (C) 2004 Elsevier B.V. All rights reserved.