Molecular dynamics simulation study on the superheating of coated argon clusters

Spherical argon clusters coated with layers of higher melting point atoms were studied by molecular dynamics (MD) simulations. Interatomic interactions were constructed from the pair wise additive Lennard–Jones atom–atom potential energy functions. A superheating of 25 K above the melting point of an uncoated Ar cluster (Ar369) was observed for the coated cluster, which consist of 369 Ar atoms coated with 566 atoms of a material with a depth well lower than ~50% that of argon. The simulation indicates that the superheating of a coated cluster is due to the lack of a free surface, or the more ordered core structure resulted from hydrostatic pressure of the high-melting coatings before the cluster reaches its melting temperature.