Stability of face-centered cubic and icosahedral Lennard-Jones clusters

Waal, B.W. van de

doi:10.1063/1.455848

Cited by 106 publications

(45 citation statements)

References 12 publications

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“…Кластер, взаимодействие между атомами которого отвечает потенциалу взаи модействия Леннарда -Джонса (22), исследован наиболее полно (см. [74][75][76][77][78][79][80][81][82][83][84][85]). Далее полученные результаты будут проанализированы с двух точек зрения.…”

Section: 3unclassified

Systems of atoms with a short-range interaction

Smirnov¹

1992

Usp. Fiz. Nauk

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Section: 3unclassified

Systems of atoms with a short-range interaction

Smirnov¹

1992

Usp. Fiz. Nauk

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“…The size of the largest crystallites ranges from 16 particles in the metastable liquid to 26 particles as the top of the barrier is approached. Previous theoretical, 43 experimental, 44 and computer simulation studies [44][45][46] indicate that for small clusters of Lennard-Jones atoms in vacuo the icosahedral structure is more stable than any of the crystalline structures. Besides, it has been suggested 32 that long-ranged icosahedral order would be favored in strongly supercooled liquids.…”

Section: A Crystallite Structurementioning

confidence: 99%

Numerical calculation of the rate of crystal nucleation in a Lennard-Jones system at moderate undercooling

Wolde

Ruiz‐Montero²,

Frenkel

1996

The Journal of Chemical Physics

728

660

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We report a computer-simulation study of the rate of homogeneous crystal nucleation and the structure of crystal nuclei in a Lennard-Jones system at moderate undercooling. The height of the nucleation barrier has been determined using umbrella sampling, whereas the barrier crossing rate is calculated using molecular dynamics simulation. The simulations clearly show that the barrier crossing is a diffusive process. Nevertheless, the kinetic prefactor in the nucleation rate is found to be some two orders of magnitude larger than predicted by classical nucleation theory. The height of the barrier is in good agreement with the theoretical prediction. Although the Lennard-Jones system has a stable face-centered cubic ͑fcc͒ phase below the melting line, the precritical nuclei are found to be mainly body-centered cubic ͑bcc͒ ordered. As they grow to their critical size, they become more fcc ordered in the core. However, the critical and postcritical nuclei retain a high degree of bcc ordering in the interface. Furthermore it is found that in the interface the density falls off faster than the structural order parameter, which is in agreement with the predictions of density functional calculations.

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“…At this crossover the most common equilibrium structure is expected to change. This technique has been applied to rare gas [2,3,4], metal [5,6,7,8] and molecular clusters [9].…”

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confidence: 99%

“…At other temperatures, however, the structure with lowest free energy needs to be found. However, perhaps through an expectation that entropic effects are unlikely to be important or are too complicated to take into account, size is usually the only variable that is considered both experimentally [10,11,12] and theoretically [2,3,4,5,6,7,8].In this paper we consider the role that entropy plays in the size evolution of cluster structure, and show that temperature can be a key variable in determining the equi- [14]. These clusters have the optimal shape for the three main types of regular packing seen in clusters: face-centred cubic, icosahedral and decahedral, respectively.…”

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Entropic Effects on the Size Dependence of Cluster Structure

Doye¹,

Calvo²

2001

Phys. Rev. Lett.

152

147

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We show that the vibrational entropy can play a crucial role in determining the equilibrium structure of clusters by constructing structural phase diagrams showing how the structure depends upon both size and temperature. These phase diagrams are obtained for example rare gas and metal clusters.PACS numbers: 61.46.+w,36.40.Mr,36.40.Ei Much of the interest in clusters or nanoparticles derives from the insights they can provide into how properties emerge and evolve on going between the atomic and molecular and bulk limits. Cluster structure provides a particular interesting example of this size evolution. At large enough sizes the clusters must display the bulk crystalline structure, but this limit may sometimes only be achieved at very large sizes (e.g. at least 20 000 atoms for sodium clusters [1]) and before that limit is reached unusual structural forms are often observed. For example, many clusters bound by van der Waals or metallic forces exhibit structures with five-fold axes of symmetry, a possibility that is forbidden in bulk crystalline materials. For these clusters the dominant structural motif typically changes from icosahedral ( Fig. 1(b)) to decahedral ( Fig. 1(c)) to face-centred-cubic (fcc) ( Fig. 1(a)) as the size increases.For many materials these structural changes occur at sizes that are too large for global optimization to be feasible. Therefore, the typical theoretical approach to systematically investigating the size evolution of cluster structure is to compare the energies of stable sequences of structures, such as the forms shown in Fig. 1. 'Crossover sizes' are then identified where the sequence with lowest energy changes. At this crossover the most common equilibrium structure is expected to change. This technique has been applied to rare gas [2,3,4], metal [5,6,7,8] and molecular clusters [9].The above approach is certainly valid at zero temperature, since the equilibrium structure then corresponds to the one with lowest energy. At other temperatures, however, the structure with lowest free energy needs to be found. However, perhaps through an expectation that entropic effects are unlikely to be important or are too complicated to take into account, size is usually the only variable that is considered both experimentally [10,11,12] and theoretically [2,3,4,5,6,7,8].In this paper we consider the role that entropy plays in the size evolution of cluster structure, and show that temperature can be a key variable in determining the equi- [14]. These clusters have the optimal shape for the three main types of regular packing seen in clusters: face-centred cubic, icosahedral and decahedral, respectively. The latter two structural types cannot be extended to bulk because of the five-fold axes of symmetry.librium structure of a cluster. A clue to this result can be garnered from the growing number of examples of solidsolid transitions in clusters where the structure changes from fcc or decahedral to icosahedral as the temperature increases [15,16,17,18,19]. The most well-investigated example...

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Stability of face-centered cubic and icosahedral Lennard-Jones clusters

Cited by 106 publications

References 12 publications

Systems of atoms with a short-range interaction

Systems of atoms with a short-range interaction

Numerical calculation of the rate of crystal nucleation in a Lennard-Jones system at moderate undercooling

Entropic Effects on the Size Dependence of Cluster Structure

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