Molecular binding at gold transport interfaces. III. Field dependence of electronic properties

The behavior of the electronic structure in a metal/molecular/metal junction as a function of the applied electric field was analyzed. It was shown that the external electric fields generally induce polarization localization on the two cluster ends. It was found that the HOMO/LUMO gap usually decreases and, for large enough fields, energy levels can cross, which presages a change of electronic state. The changes in the geometry both of the molecule and the molecule/cluster interface upon application of the electric field were shown by the calculations.