Predicted properties and melting transition of krypton layers physisorbed onto Lennard-Jones spheres

Abstract

We report the results of constant-temperature, constant-density, molecular-dynamics simulations of the melting transition of Kr atoms physisorbed onto small Lennard-Jones spheres. Adlayer depletion takes place when free boundary conditions are used but utilization of a soft reflecting shell results in a broad melting transition at around Tϭ65 K without any appreciable hysteresis. We introduce structural and bondorientational parameters and utilize thermodynamic parameters to monitor the behavior of the system. The spherical geometry causes compression of the neighbor distances with respect to those for the corresponding planar case, causing enhanced interaction of the neighbor shells via interstitials/vacancies, the nature of which is further elucidated using the bond-orientational information. Quantities related to the radial degree of freedom change slowly during melting, and bond-orientational order of the Kr lattice persists well into the fluid.

Statistical Mechanics of Liquids and Fluids in Curved Space

“…Unsurprisingly, they have also been developed for investigating fluid and condensed phases in curved space. Monte Carlo simulations for short-range [13,[40][41][42][57][58][59][60][61][62] and longrange Coulombic-like [52,53,63,64] potentials in two and three-dimensional geometry, and more seldom Molecular Dynamic studies in two-dimensional spherical [65][66][67] and hyperbolic manifolds [31,32,[68][69][70], have been performed . Early on, numerical packing protocols have also been considered in spherical [71,72] and hyperbolic [11] geometries.…”

Gaussian approximation to single particle correlations at and below the picosecond scale for Lennard-Jones and nanoparticle fluids

“…This can be accomplished by choosing M to be 1 + R 3 , leading to a maximum mass ratio of 217 between the nanoparticles and the fluid LJ particles. One can show that the result of integrating the LJ potentials corresponding to all the points in the spherical nanoparticle is that a nanoparticle interacts with a fluid LJ particle through the potential [9,21] V AB (r) = 4M…”

“…Such nanoclusters have a variety of applications, from material coatings to drug delivery by hollow clusters. Both the individual behaviour of nanosized particles [9,10,11] as well as their collective behaviour, such as the increased heat conductance in dilute suspensions of nanoparticles (so-called nanofluids) [1], have received considerable attention [8].…”

Effective pair potentials for spherical nanoparticles

“…Such systems have applications ranging from material coatings to drug delivery. 8,9 For colloidal systems, collective behavior has been the focus of much research, 6,10 while nanoclusters are often studied as isolated objects, 11,12,13,14,15 despite interesting collective phenomena such as the increased heat conductance in dilute nanoparticle suspensions 2 and self-assembly. 6 To study the collective properties of nanoparticles in suspension, one would expect that a detailed description of the internal structure of the clusters is not necessary, especially if the nanoparticles are more or less solid.…”

“…Similar approaches to the problem of constructing effective potentials have been used before, but only for specific cases. 1,13,14,15,16,17 The current paper is devoted to the general method of deriving effective pair potentials for nanoparticles from the basic pair potential of their constituents. The possibility of overlapping and embedded particles is specifically treated as well.…”