Towards the directional transport of molecules on surfaces

Abstract Control of the translational motion of individual molecules on surfaces is necessary for the development of novel methods for mass transport, separations, enantiopurifications and reactions, as well as in new applications including pumps, sensors, and assembly. Herein we discuss a concept whereby a flashing temperature ratchet-like mechanism comprised of asymmetric potential energy landscapes of individual molecules on surfaces coupled with excitation by electrons may enable directed molecular transport in a wide variety of nanoscale systems. Towards this goal we have studied the inelastic electron tunneling induced diffusion of molecules on surfaces with defined potential energy landscapes including surface step edges and low symmetry (110) facetted surfaces. Our results indicate that, with careful selection of components, 1D motion can be induced but that unidirectionality is still elusive.