Influence of cooperative effects on the formation of water trimers on Pt(111)

Calculations on small platinum-water clusters demonstrate the importance of cooperative effects on the formation of a water bilayer structure on the p latinum(111) surface. If the orientation of the bridging water molecule is allowed to relax during the simulation of this bilayer, one hydrogen bond i s broken in favor of the other. The desorption energy of water from the rel axed model cluster is found to be in better agreement with published therma l desorption spectra data than desorption energies arising from an ideal ic elike bilayer structure.