Anisotropy effect of multi-center Lennard-Jones molecular clusters

Models of randomly packed hard molecules of Multi-Center Lennard-Jones (MCLJ) clusters exhibit some features of anisotropy effects. To investigate the anisotropy effect on the structures of molecular clusters, four highly symmetrical molecules are modeled: 4-atom tetrahedron (TLJ), 6-atom octahedron (OLJ), 8 atom cube (CLJ), and 12-atom icosahedron (ILJ). The intermolecular interactions are described using the MCLJ model. Using the funnel hopping algorithm, we located the putative global minimum structures of these four MCLJ molecular clusters up to cluster size N = 80. The structural patterns of these MCLJ clusters are much different to that of Lennard-Jones clusters, and some new rules and structures are found. The structures of TLJ clusters are most irregular due to the highest anisotropy effect of the tetrahedral molecule. For OLJ clusters, a new structural pattern, rhombic dodecahedron, is viewed. The structures of CLJ clusters are also interesting, which look like oblique face-centered cubic (fcc) structures. For ILJ clusters, icosahedral motifs are favored at cluster size N <= 19, and fcc motifs are favored more at N > 19. (C) 2016 Published by Elsevier B.V.