Global minima of Al_N, Au_Nand Pt_N,N⩽ 80, clusters described by the Voter–Chen version of embedded-atom potentials

Abstract

Using the basin-hopping Monte Carlo minimization approach we report the global minima for aluminium, gold and platinum metal clusters modelled by the Voter-Chen version of the embeddedatom model potential containing up to 80 atoms. The virtue of the Voter-Chen potentials is that they are derived by fitting to experimental data of both diatomic molecules and bulk metals simultaneously. Therefore, it may be more appropriate for a wide range of the size of the clusters. This is important since almost all properties of the small clusters are size dependent. The results show that the global minima of the Al, Au and Pt clusters have structures based on either octahedral, decahedral, icosahedral or a mixture of decahedral and icosahedral packing. The 54-atom icosahedron without a central atom is found to be more stable than the 55-atom complete icosahedron for all of the elements considered in this work. The most of the Al global minima are identified as some fcc structures and many of the Au global minima are found to be some low symmetric structures, which are both in agreement with the previous experimental studies.

Theoretical study of the melting of aluminum clusters

“…18,19,20 Similar results were obtained with Voter-Chen 27 and Gupta 28 models. Both show special stabilities also for the 38-atom truncated octahedron and for the Mackay icosahedron 24,25 , except that the Gupta potential favours the complete 55-atom icosahedron. 24 Very different structures were found, however, with the Sutton-Chen 29 and glue 30 potentials.…”

“…However, in spite of the experimental 6,7 and theoretical 8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25 effort, a consensus has not yet been achieved about the structure of many of the experimentally observed magic numbers. Only for large sizes (N > 250) the structure of Al clusters seems to have been rationalized.…”

“…19,20,21,22,23,24,25 However, the results show a strong dependence on the model potential used. The Murrell-Mottram potential 26 predicts a competition between fcc and icosahedral structures in the size regime N = 2-55, with strong magic numbers for the 38-atom truncated octahedron and the 54-atom uncentered Mackay icosahedron.…”

Structures and stabilities of Aln+, Aln, and Aln− (n=13–34) clusters

“…A controversy has arisen regarding the correct global minimum ͑GM͒ for Al 13 : the optimizations based on parametrized potential models 32,34,35,41,42,46,52 invariably predict an icosahedral structure, but these methods do not contain an explicit description of the electronic degrees of freedom and their accuracy is questionable. A majority of the ab initio calculations ͓mostly based on density functional theory ͑DFT͒ and differing in the election of exchangecorrelation functional, aluminum pseudopotential, and basis set͔ predict an icosahedron as the most stable structure, [22][23][24][25]27,28,30,33,37,39,45 but a small number of calculations 26,31,38,48,49 predict a decahedron to be more stable.…”

Electron Affinity of Al13: A Correlated Electronic Structure Study

“…17 Other studies describe the decahedral and icosahedral neutral isomers as competing structures due to their small energy difference. 18 A Car-Parrinello study 19 finds a single, welldefined, slightly distorted icosahedral minimum energy structure for Al 13 , while a model potential basin-hopping Monte Carlo simulation 20 finds the point group of Al 13 to be I h . A study 21 utilizing a genetic algorithm coupled with a tight-binding potential, whose low-energy structure candidates were further optimized with local density approximation DFT, finds an icosahedral ground state for Al 13 .…”