Structural properties of solid nuclei forming in Lennard-Jones clusters during simulated cooling

Liquid Lennard-Jones clusters composed of N = 923 particles were frozen using Monte Carlo simulated cooling in order to analyse the process of nucleation of new phase. Among 100 final clusters obtained in independent simulations runs, 15 cases of creation of layered fcc/hcp structure were selected for detailed analysis. Formation of nuclei was carefully analysed to find their stability with respect to the number and composition of particles, geometric and structural properties as well as their position in the cluster. The analysis was carried out by extensive use of structural analysis, cluster detection procedure and visualisation. The investigated subcritical nuclei are very unstable regarding their size, shape, structure and composition. Larger nuclei are more stable keeping their layered structure, although migration of particles between the surfaces of solid nucleus and liquid cluster is large. Creation of nuclei occurs inside clusters, sometimes they overlap the cluster centre, but elongated or ramified nuclei tend to be contacted with cluster surface and grow toward the cluster centre.