Molecular motion to substrate step edges

Upon adsorption at low temperature, isolated benzene molecules are attracted and move to step edges on the Ni{110} surface. The molecules had well-defined incident trajectories onto a Ni{110} crystal maintained at 4 K so as to prevent thermally activated diffusion. We used low temperature scanning tunneling microscopy to measure the excess density of molecules at step edges, the adsorbate distributions on terraces, and the mean accommodation lengths. The incident azimuthal direction is not significant compared to the strong local attraction of the substrate step edges.