Incipient triple point for adsorbed xenon monolayers: Pt(111) versus   graphite substrates
  Simulation evidence of an incipient triple point is reported for xenon submonolayers adsorbed on the (111) surface of platinum. This is in stark contrast to the "normal" triple point found in simulations and experiments for xenon on the basal plane surface of graphite. The motions of the atoms in the surface plane are treated with standard 2D "NVE" molecular dynamics simulations using modern interactions. The simulation evidence strongly suggests an incipient triple point in the 120-150 K range for adsorption on the Pt (111) surface while the adsorption on graphite shows a normal triple point at about 100 K. 
Anthony D. Novaco, L. W. Bruch, Jessica Bavaresco
cond-mat.mtrl-sci cond-mat.stat-mech