UNIAXIAL INCOMMENSURATE RARE-GAS-MONOLAYER SOLIDS .2. APPLICATION TO XE/PT(111)

An effective interaction model is reported for the interactions of xenon adsorbed on the (111) face of platinum. Many structural properties of the observed uniaxial incommensurate phase are reproduced. The uniaxial phase has a large linear thermal expansion and a commensurate triangular lattice becomes the minimum-free-energy phase at intermediate temperatures. A multiparameter monolayer interaction model, constructed from terms used for other physisorption systems, has too weak a short-range adatom-adatom repulsion. Analysis and reinterpretation of data for the heats of adsorption also show the need for an additional repulsive term.