Growth Pattern of Truncated Octahedra in Al_N (N ≤ 310) Clusters

Abstract

The growth sequence of aluminum clusters containing up to 310 atoms was studied. The interaction of aluminum atoms is modeled by the NP-B potential fitted by highly accurate electronic structure datum for aluminum clusters and nanoparticles. The putative global minimum structures of Al(2-310) clusters are obtained by dynamic lattice searching (DLS) and DLS with constructed cores (DLSc) method. Lower energy structures of Al(63) and Al(64) were found in comparison with the previously reported Al(2-65) clusters. In the optimized structures of Al(63-310), all clusters are identified as truncated octahedra (TO) except for five decahedral structures at Al(64), Al(72), Al(74), Al(76), and Al(101), four stacking fault face-centered cubic structures at Al(91), Al(99), Al(129), and Al(135), and one icosahedron at Al(147). Therefore, the structural transition from small clusters to bulk metal may occur around Al(65). At the same time, the results show that aluminum clusters adopt TO growth pattern, and the growth is found to be based on six complete TO at Al(38), Al(79), Al(116), Al(140), Al(201), and Al(260).

Geometrical structures and energetics of gold clusters from Au13 to Au300

“…The inner cores with the same kinds of configurations are, thus, used in the DLSc method, respectively. The Dh and FCC cores have been constructed in our previous work [38]. Figure 2 shows an 83-atom SF FCC structure with the atomic distribution of every layer, and the mid-layer in the figure is a symmetrical plane.…”

“…Moreover, Au clusters with 33-37 atoms are grown based on the decahedral motif. However, at Au 38 , a complete truncated octahedron is formed, and one extra atom of Au 39 is added to one (100) face of Au 38 . In Au 40-48 clusters, the segment of Mackay icosahedra can be found, except for decahedral motifs at Au 41 , Au 43 , and Au 47 .…”

“…The transition from flat-cage (Au 15 and Au 16 ) to hollow-cage structure (Au 17 and Au 18 ) was found at Au 17 , and the variation from hollow-cage to pyramidal structure was recognized at Au 19 [7,8]. For medium-sized gold clusters, experimental and theoretical study showed that the structures of Au 36 -to Au 38 -were found to be core-shell type structures all with a tetrahedral four-atom core, and at Au 38 -the appearance of a fragment of the face centered cubic (FCC) bulk gold implied that the cluster-to-bulk transformation starts to emerge at the medium size range [9]. Moreover, time-dependent density functional theory (TDDFT) was used to calculate the optical absorption spectra of gold clusters in the size range of 20-171 [10].…”

“…The DLS method has been successfully used for optimization of Lennard-Jones clusters up to 500 atoms [32], Morse N (N B 210) clusters [33], (C60) N (N B 150) clusters [34]. A variation of DLS named as the DLS with constructed core (DLSc) method [35] has been developed to the optimization of large clusters, for example, Lennard-Jones clusters up to 670 atoms, silver clusters up to 310 atoms [36,37], gold clusters up to 200 atoms [17], and aluminum clusters up to 500 atoms [38,39].…”

Theoretical Study of Structural Symmetry in Ternary Clusters

“…The symmetry of a molecule is described by one standard designation like C 2v . For example, in the stable structures of LJ clusters, PGs of LJ 4 , LJ 13 [24]. Besides the mono-elemental clusters, binary or ternary clusters also have the symmetry, e.g., Ag 33 Pd 5 C 2v [20], Cu 13 Ag 2 Au 40 C 2 [7].…”