Theoretical study of Cu–Au nanoalloy clusters using a genetic algorithm

Abstract

A study has been made of the structures and stabilities of copper and gold clusters and copper–gold nanoalloy clusters, with up to 56 atoms, modeled by the many-body Gupta potential. For pure copper clusters, the lowest energy structures are found to be based on icosahedral packing, while pure gold clusters tend to form less symmetrical (often amorphous) structures. In a number of cases, the replacement of a single gold atom by copper is found to be sufficient to convert the structure to that of the more symmetrical copper cluster. The lowest energy clusters are generally more difficult to find for the bimetallic clusters than for the pure metallic clusters, due to the presence of homotops (related by permuting Cu and Au atoms), as well as geometrical isomers. The structures of the lowest energy bimetallic clusters exhibit primarily icosahedral packing, with (CuAu)M and (CuAu3)M clusters tending to form layered structures and (Cu3Au)M clusters showing greater Cu–Au mixing.

Structure and stability of copper clusters: A tight-binding molecular dynamics study

“…These results can be compared with the genetic algorithm study on copper clusters by Darby et al [26], using Gupta potential. In agreement with the present study, Darby et al found that most of the clusters in this regime adopt structures based on icosahedron.…”

“…They also found exceptions to the icosahedral growth at around Cu 40 , where the structures adopt decahedron like geometries (exact numbers are not available in the Ref. [26]). But the present study disagree with the genetic algorithm study in two points.…”

“…D'Agostino carried molecular dynamics using a quasiempirical potential derived from a tight-binding approach for nearly 1300 atoms [24]. More recently Darby et al carried geometry optimization by genetic algorithm using Gupta potential [25] for Cu n , Au n and their alloy clusters in the size range n ≤ 56 [26]. These kinds of empirical atomistic potentials are found to be good to predict ground state geometries but can not predict electronic properties such as electronic shell closing effect for n =2, 8, 20, 40, ..., highest occupied-lowest unoccupied molecular level (HOMO-LUMO) gap energy and ionization potential.…”

Моделирование Взаимодействия Двудольных Биметаллических Кластеров С Низкоэнергетическими Кластерами Аргона

“…При этом, объектами пристального внимания как с практической, так и с академической точек зрения являются металлические кластеры [3]. Среди посвященных им исследований существует много работ по изучению пар компонен-тов кластеров Cu−Au [4][5][6] и Ni−Al [7,8]. Их форма, атомная структура, композиция и сегрегационные свой-ства являются объектами исследования, поскольку они влияют на химическую активность и каталитические свойства [9,10].…”

Mechanical properties of metallic nanowires using tight-binding model

“…It should be noted that, even in the current state of the art in the development of highperformance computers, an ab initio simulation of this system remains impossible [2][3][4].…”