Electronic shell structure of group-IIIA metal atomic clusters

Schriver, K. E.; Persson, John L.; Honea, Eric C.; Whetten, Robert L.

doi:10.1103/physrevlett.64.2539

Cited by 255 publications

(173 citation statements)

References 27 publications

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“…The drop in the melting temperature for Al n + clusters with 56 atoms was initially attributed to a geometry change 65 but more recent the- 55 + shows an enhanced stability because it is an electron shell closing, so the drop in melting temperature for Al 56 + might also be induced by the opening of a new electron shell. The electron shell closing for Al 55 + has been confirmed by photoionization experiments 66 but, considering the computational difficulties of locating the global minimum energy structures via first-principles calculations, we think theory cannot yet reliably reject the possibility of a structural change.…”

Section: Preliminary Discussion Of Experimental Resultsmentioning

confidence: 99%

Substituting a copper atom modifies the melting of aluminum clusters

Cao

Starace

Neal

et al. 2008

The Journal of Chemical Physics

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Heat capacities have been measured for Al n−1 Cu − clusters ͑n =49-62͒ and compared with results for pure Al n + clusters. Al n−1 Cu − and Al n + have the same number of atoms and the same number of valence electrons ͑excluding the copper d electrons͒. Both clusters show peaks in their heat capacities that can be attributed to melting transitions; however, substitution of an aluminum atom by a copper atom causes significant changes in the melting behavior. The sharp drop in the melting temperature that occurs between n = 55 and 56 for pure aluminum clusters does not occur for the Al n−1 Cu − analogs. First-principles density-functional theory has been used to locate the global minimum energy structures of the doped clusters. The results show that the copper atom substitutes for an interior aluminum atom, preferably one with a local face-centered-cubic environment. Substitution does not substantially change the electronic or geometric structures of the host cluster unless there are several Al n + isomers close to the ground state. The main structural effect is a contraction of the bond lengths around the copper impurity, which induces both a contraction of the whole cluster and a stress redistribution between the Al-Al bonds. The size dependence of the substitution energy is correlated with the change in the latent heat of melting on substitution.

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Section: Preliminary Discussion Of Experimental Resultsmentioning

confidence: 99%

Substituting a copper atom modifies the melting of aluminum clusters

Cao

Starace

Neal

et al. 2008

The Journal of Chemical Physics

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“…It is known that while the electronic factors determine cluster stability for alkali metal clusters [52], packing and surface energy effects dominate on the structure of alkaline earth elements, such as calcium and strontium [51]. Aluminium places at a central position between the regimes of electronic and geometric shells [45]. Martin's mass spectroscopic studies [51] have shown that Al clusters with up to a few hundred atoms have face-centred cubic (fcc) packing structures.…”

Section: A Aluminium Clustersmentioning

confidence: 99%

“…In these model potential studies carried out by random search, simulated annealing or genetic algorithms, Al clusters are described by an empirical many-body potential [34], two-plus-three body Murrell-Mottram potential [35,36,37], Gupta [38] or Sutton-Chen [39] potentials. Similarly, the experimental studies on Al clusters [40,41,42,43,44,45,46,47,48,49,50,51] go back to the middle of the 1980s. It is known that while the electronic factors determine cluster stability for alkali metal clusters [52], packing and surface energy effects dominate on the structure of alkaline earth elements, such as calcium and strontium [51].…”

Section: A Aluminium Clustersmentioning

confidence: 99%

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

Sebetci

Güvenç

2005

Modelling Simul. Mater. Sci. Eng.

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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.

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“…History began with the milestone discovery of a shell structure in the electronic spectra of small nanoclusters of monovalent alkali atoms such as Na and K (~10 2 or fewer delocalized electrons) by Walter Knight and co-workers (Knight et al 1984). This was later followed by observations of shell structures in Al, Ga, In, Zn and Cd clusters Lermé et al 1999;Poudel et al 2008;Ruppel and Rademann 1992;Schriver et al 1990) as well as cluster ions of Cu, Ag and Au ).…”

Section: Super-atom Model Is a Specific Way Of Viewing And Rationalizmentioning

confidence: 99%