Ternary and quaternary Lennard-Jones atomic clusters: The effects of atomic sizes on the compositions, geometries, and relative stability

Abstract

Global-minimum geometries of ternary and quaternary Lennard-Jones clusters have been calculated with constraints on atomic compositions of the clusters. In the present study, the constraints were removed to obtain optimal compositions. The size ratios of the largest-sized atom to the smallest-sized one ranged from 1.1 to 1.6 whereas the depths of the interatomic potentials were constant. The heuristic method combined with the geometrical perturbations and atom-type conversion was used to search for the global minima of the clusters with up to 50 atoms. The smallest-sized and largest-sized atoms usually occupy cores and outer shells, respectively, and the atoms with intermediate sizes are often lacking. The size ratio has pronounced effects on the compositions, structures, and relative stability of the clusters.