AVS 50th International Symposium
    Surface Science Tuesday Sessions
       Session SS1-TuA

Invited Paper SS1-TuA7
The Growth of Water Monolayers on Pd(111)

Tuesday, November 4, 2003, 4:00 pm, Room 326

Session: Water at Interfaces II: Adsorbed Layers
Presenter: M. Salmeron, Lawrence Berkeley National Lab, University of California at Berkeley
Authors: T. Mitsui, Lawrence Berkeley National Lab, University of California at Berkeley
E. Fomin, Lawrence Berkeley National Lab, University of California at Berkeley
M.K. Rose, Lawrence Berkeley National Lab, University of California at Berkeley
D.F. Ogletree, Lawrence Berkeley National Lab, University of California at Berkeley
M. Salmeron, Lawrence Berkeley National Lab, University of California at Berkeley
Correspondent: Click to Email
Using STM at low temperature we have followed the structures formed by water growing on a clean Pd(111) substrate. Starting with the monomers the process of cluster formation proceeds via formation of dimers, trimers and so forth. We found a surprising increase in diffusivity for the small clusters (2 to 4 molecules), which we attribute to mismatch between the cluster’s structure and the substrate. Cluster mobility decreases substantially when the sizes is 5 and above. Continued adsorption of water results in the formation of honeycomb-like structures reminiscent of ice-like hexagonal bilayers. These structures are limited in size below 90K approximately, indicating kinetic limitations to the growth. Above 100K more extensive honeycomb structures are formed. Above 130K new structures with larger periodicity are formed. The observations will be discussed in light of recent wetting models involving the possible partial dissociation of the first water layer.