  We investigate the effects of lateral interactions on the conductance of two
molecules connected in parallel to semi-infinite leads. The method we use
combines a Green function approach to quantum transport with density functional
theory for the electronic properties. The system, modeled after a
self-assembled monolayer, consists of benzylmercaptane molecules sandwiched
between gold electrodes. We find that the conductance increases when
intermolecular interaction comes into play. The source of this increase is the
indirect interaction through the gold substrate rather than direct
molecule-molecule interaction. A striking resonance is produced only 0.3 eV
above the Fermi energy.
