Water Diffusion and Clustering on Pd(111)

摘要: The adsorption, diffusion, and clustering of water molecules on a Pd(111) surface were studied by scanning tunneling microscopy. At 40 kelvin, low-coverage adsorbs in the form isolated molecules, which diffuse hopping to nearest neighbor sites. Upon collision, they first dimers, then trimers, tetramers, so on. mobility these species increased several orders magnitude when tetramers formed, decreased again cluster contained five or more molecules. Cyclic hexamers found be particularly stable. They grow with further exposure commensurate hexagonal honeycomb structure relative substrate. These observations illustrate change strength between intermolecular hydrogen bonds molecule-substrate as function size, key property that determines wetting properties materials.