Structure determination in 55-atom Li–Na and Na–K nanoalloys

Aguado, Andrés; López, José Manuel

doi:10.1063/1.3479396

Cited by 32 publications

(56 citation statements)

References 64 publications

(63 reference statements)

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“…Our computational strategy is exactly the same as in our previous paper on Li-Na and Na-K mixtures; 36 so, we provide here just a brief account of it and refer the reader to our previous work for a full exposition of the theoretical method.…”

Section: Methodsmentioning

confidence: 99%

“…All the technical details of the BH runs are the same as in Ref. 36, with only one exception: in this work, we have found it convenient to remove the swap moves (interchanging the identity of two randomly chosen A-and B-atoms) when sampling the potential energy surface. These trial moves always result in isomers with a very high energy, as they oppose the natural tendency of the bigger Cs atoms to segregate to the cluster surface.…”

Section: Methodsmentioning

confidence: 99%

“…Following the work of Ferrando et al, 18 those isomers are selected on the basis of structural descriptors in order to enhance the structural diversity (see Ref. 36 for full details of our procedure). The first-principles calculations themselves have been performed at the Kohn …”

Section: Methodsmentioning

confidence: 99%

“…36 In this paper, we enlarge our description of alkali nanoalloys by considering mixtures with a much larger size mismatch, namely Na x Cs 55−x and Li x Cs 55−x . We are mainly interested in identifying trends in the structure and stability of bimetallic nanoalloys as a function of the size mismatch, and for this reason we will offer a systematic comparison of the four systems, reproducing some of the results from the previous paper when these are needed for a clearer exposition of trends.…”

Section: Introductionmentioning

confidence: 99%

“…Finally, purely quantum electron shell effects 16,36 or even magnetic effects 15 may also have a strong influence on the nanoalloy structures.…”

Section: Introductionmentioning

confidence: 99%

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Identifying structural and energetic trends in isovalent core-shell nanoalloys as a function of composition and size mismatch

Aguado

López²

2011

The Journal of Chemical Physics

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We locate the putative global minimum structures of Na x Cs 55−x and Li x Cs 55−x nanoalloys through combined empirical potential and density functional theory calculations, and compare them to the structures of 55-atom Li-Na and Na-K nanoalloys obtained in a recent paper [A. Aguado and J. M. López, J. Chem. Phys. 133, 094302 (2010)]. Alkali nanoalloys are representative of isovalent metallic mixtures with a strong tendency towards core-shell segregation, and span a wide range of size mismatches. By comparing the four systems, we analyse how the size mismatch and composition affect the structures and relative stabilities of these mixtures, and identify useful generic trends. The Na-K system is found to possess a nearly optimal size mismatch for the formation of poly-icosahedral (pIh) structures with little strain. In systems with a larger size mismatch (Na-Cs and Li-Cs), frustration of the pIh packing induces for some compositions a reconstruction of the core, which adopts instead a decahedral packing. When the size mismatch is smaller than optimal (Li-Na), frustration leads to a partial amorphization of the structures. The excess energies are negative for all systems except for a few compositions, demonstrating that the four mixtures are reactive. Moreover, we find that Li-Cs and Li-Na mixtures are more reactive (i.e., they have more negative excess energies) than Na-K and Na-Cs mixtures, so the stability trends when comparing the different materials are exactly opposite to the trends observed in the bulk limit: the strongly non-reactive Li-alkali bulk mixtures become the most reactive ones at the nanoscale. For each material, we identify the magic composition x m which minimizes the excess energy. x m is found to increase with the size mismatch due to steric crowding effects, and for Li x Cs 55−x the most stable cluster has almost equiatomic composition. We advance a simple geometric packing rule that suffices to systematize all the observed trends in systems with large size mismatch (Na-K, Na-Cs, and Li-Cs). As the size mismatch is reduced, however, electron shell effects become more and more important and contribute significantly to the stability of the Li-Na system.

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Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

“…Finally, purely quantum electron shell effects 16,36 or even magnetic effects 15 may also have a strong influence on the nanoalloy structures.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Identifying structural and energetic trends in isovalent core-shell nanoalloys as a function of composition and size mismatch

Aguado

López²

2011

The Journal of Chemical Physics

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On the use of big‐bang method to generate low‐energy structures of atomic clusters modeled with pair potentials of different ranges

2011

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The efficiency of the so-called big-bang method for the optimization of atomic clusters is analysed in detail for Morse pair potentials with different ranges; here, we have used Morse potentials with four different ranges, from long- ρ = 3) to short-ranged ρ = 14) interactions. Specifically, we study the efficacy of the method in discovering low-energy structures, including the putative global minimum, as a function of the potential range and the cluster size. A new global minimum structure for long-ranged ρ = 3) Morse potential at the cluster size of n= 240 is reported. The present results are useful to assess the maximum cluster size for each type of interaction where the global minimum can be discovered with a limited number of big-bang trials.

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Enhanced quantum size effect in Li and Na clusters via rare gas doping

Guo

Liu

et al. 2016

Int J of Quantum Chemistry

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Albeit its chemical inertness, rare gas doping can substantially enhance the quantum size effect of nanocrystals, yet little attention has been paid on this fascination and the mechanism behind remains unclear. Here, we show that the rare gas dopant breaks bonds of its neighboring atoms, which effects the same to atomic under‐coordination on the bond strain, energy quantum entrapment, and valence electron polarization of Li and Na clusters. Consistency between density functional theory calculation and the bond‐order‐length‐strength correlation prediction revealed that the bond strain by 16.86% and 21.12% before and after He doping for Na30 clusters. Observations suggest an effective yet simple means to modulate the physical properties by doping the inert gases.

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Structure determination in 55-atom Li–Na and Na–K nanoalloys

Cited by 32 publications

References 64 publications

Identifying structural and energetic trends in isovalent core-shell nanoalloys as a function of composition and size mismatch

Identifying structural and energetic trends in isovalent core-shell nanoalloys as a function of composition and size mismatch

On the use of big‐bang method to generate low‐energy structures of atomic clusters modeled with pair potentials of different ranges

Enhanced quantum size effect in Li and Na clusters via rare gas doping

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