A theoretical study of atom ordering in copper–gold nanoalloy clusters

Abstract

Energy calculations have been carried out on high symmetry icosahedral and cuboctahedral Cu-Au nanoalloy clusters of various compositions, with the interatomic interactions modelled by the Gupta many-body potential. For each composition, the lowest energy isomers (''homotops'') tend to have predominantly Au atoms on the surface and Cu atoms in the core, and this phenomenon is explained in terms of surface energy, atomic size and trends in cohesive energies. A number of order parameters and mixing energies have been introduced and it is shown that there is good correlation between the cluster binding energy and the average distance of the Au atoms from the centre of the cluster. Comparisons are made with previous theoretical calculations on Cu-Au clusters, as well as with experimental studies of the structures and atom ordering of deposited Cu-Au particles.

Growth format, electronic architecture, magnetic, and optical properties of aromatic cyclo‐Cu3Au3 homotops

“…The mixing energy, DE mix , that is the change in cluster binding energy upon mixing, is defined as 44,45 It can be seen that all cyclo-Au 3 Cu 3 homotops are predicted to be bound with respect to their dissociation either to the AuCu diatomic species or to free Au and Cu atoms in their ground states. The lowest energy homotops, 1 (global minimum), 2 and 3, have predominantly Au atoms in the periphery and Cu atoms in the core.…”

Optimization of bimetallic Cu–Au and Ag–Au clusters by using a modified adaptive immune optimization algorithm

“…Much effort was also made for modeling of metallic and bimetallic clusters. [34][35][36][37][38][39][40][41][42][43][44][45][46][47] The main potential function applied for optimizing bimetallic Cu-Au clusters is the many-body Gupta potential. To study the Immune optimization algorithm (IOA) [49][50][51] is a kind of global optimization algorithm and has been successfully used in the field of science and engineering.…”

Gold Goes Nano—From Small Clusters to Low‐Dimensional Assemblies

“…Some of the larger clusters were characterized only recently, such as [Au 10 (PPh 3 ) 7 {(S 2 C 2 (CN) 2 } 2 ] (Figure 2 C), [6] [15][16][17] Cl x ] (R any organic ligand). [7] The color of these compounds ranges from yellow to orange, red, and even green (due to an additional absorption maximum in the blue visible range).…”

“…[15] Moreover, there is some indication that the magic clusters Au 38 , Au 55 , or Au 75 are disordered in the gas phase. [16] The accurate description of such large systems by quantum theoretical procedures such as ab initio or density functional theory, or by semiempirical and many-body expansions of the interaction potential [17] therefore poses a significant challenge to future computational work.…”