Molecular motion to substrate step edges

Upon adsorption at low temperature, isolated benzene molecules are attracte d and move to step edges on the Ni[110] surface. The molecules had well-def ined incident trajectories onto a Ni[110] crystal maintained at 4K so as to prevent thermally activated diffusion. We used low temperature scansing tu nneling microscopy to measure the excess density of molecules at step edges , the adsorbate distributions on terraces, and the mean accommodation lengt hs. The incident azimuthal direction is not significant compared to the str ong local attraction of the substrate step edges. (C) 2000 Elsevier Science B.V. All rights reserved.