Calculated phase boundary including corrugation effects for krypton layers physisorbed onto spherical substrates

A molecular-dynamics technique is utilized to calculate the melting curve of submonolayer and complete layers of krypton atoms physisorbed onto a spherical substrate. Two models of the substrate are used. In the first model the substrate is treated as a spherical continuum whose differential elements interact with krypton atoms via Lennard-Jones ~LJ! potential. Hysteresis is present in the melting transition for low coverages, which disappears as the melting becomes more gradual near complete coverage. The melting temperature at completion is very sensitive to second-layer promotion, which in turn depends strongly on the radial boundary conditions. In the second model the melting transition is also examined for 100 Kr atoms adsorbed onto spheres that exhibit corrugation in their potential interactions with the asdorbate. Addition of corrugation in the form of a C60 lattice effectively serves to merely raise the average LJ substrate sphere density slightly and leave the melting transition unaffected, but replacing the LJ sphere with a cubic carbon lattice raises the melting temperature by about 3 K ~4.6%! while dramatically affecting the desorption behavior of the adlayer and lowering its spatial order. Various bond-orientational distributions and snapshot configurations are employed in understanding the completion process.