# Icosahedral growth and non-metal-metal transition in strontium clusters

About: This article is published in Scripta Materialia.The article was published on 2001-05-18. It has received 1 citations till now. The article focuses on the topics: Cluster (physics) & Strontium.

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TL;DR: Investigating the effect of impurity atoms on the structure and electronic properties of lead clusters reveals that the interplay between the atomic and electronic structure is crucial to understand the stability of these clusters.

Abstract: A systematic theoretical study of the PbnM (M=C, Al, In, Mg, Sr, Ba, and Pb; n=8, 10, 12, and 14) clusters have been investigated to explore the effect of impurity atoms on the structure and electronic properties of lead clusters. The calculations were carried out using the density functional theory with generalized gradient approximation for exchange-correlation potential. Extensive search based on large numbers of initial configurations has been carried out to locate the stable isomers of PbnM clusters. The results revealed that the location of the impurity atom depends on the nature of interaction between the impurity atom and the host cluster and the size of the impurity atom. Whereas, the impurity atoms smaller than Pb favor to occupy the endohedral position, the larger atoms form exohedral capping of the host cluster. The stability of these clusters has been analyzed based on the average binding energy, interaction energy of the impurity atoms, and the energy gap between the highest occupied and lowest unoccupied energy levels (HLG). Based on the energetics, it is found that p-p interaction dominates over the s-p interaction and smaller size atoms interact more strongly. The stability analysis of these clusters suggests that, while the substitution of Pb by C or Al enhances the stability of the Pbn clusters, Mg lowers the stability. Further investigations of the stability of PbnM clusters reveal that the interplay between the atomic and electronic structure is crucial to understand the stability of these clusters. The energy gap analysis reveals that, while the substitution of Mg atom widens the HLG, all other elements reduce the gap of the PbnM clusters.

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TL;DR: An efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set is presented and the application of Pulay's DIIS method to the iterative diagonalization of large matrices will be discussed.

Abstract: We present an efficient scheme for calculating the Kohn-Sham ground state of metallic systems using pseudopotentials and a plane-wave basis set. In the first part the application of Pulay's DIIS method (direct inversion in the iterative subspace) to the iterative diagonalization of large matrices will be discussed. Our approach is stable, reliable, and minimizes the number of order ${\mathit{N}}_{\mathrm{atoms}}^{3}$ operations. In the second part, we will discuss an efficient mixing scheme also based on Pulay's scheme. A special ``metric'' and a special ``preconditioning'' optimized for a plane-wave basis set will be introduced. Scaling of the method will be discussed in detail for non-self-consistent and self-consistent calculations. It will be shown that the number of iterations required to obtain a specific precision is almost independent of the system size. Altogether an order ${\mathit{N}}_{\mathrm{atoms}}^{2}$ scaling is found for systems containing up to 1000 electrons. If we take into account that the number of k points can be decreased linearly with the system size, the overall scaling can approach ${\mathit{N}}_{\mathrm{atoms}}$. We have implemented these algorithms within a powerful package called VASP (Vienna ab initio simulation package). The program and the techniques have been used successfully for a large number of different systems (liquid and amorphous semiconductors, liquid simple and transition metals, metallic and semiconducting surfaces, phonons in simple metals, transition metals, and semiconductors) and turned out to be very reliable. \textcopyright{} 1996 The American Physical Society.

64,484 citations

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TL;DR: A review of progress in calculating properties related to the electronic structure of solids is presented in this article with emphasis on the pseudopotential method, where the pseudoprocessor is used to calculate properties of the solids.

Abstract: A review of progress in calculating properties related to the electronic structure of solids is presented with emphasis on the pseudopotential method.

1,232 citations

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TL;DR: A simple modification of a standard pseudopotential generation scheme is developed, and the new, smoother potentials are shown to decay significantly faster in reciprocal space, with no loss of transferability.

Abstract: Modern norm-conserving pseudopotentials are constructed to satisfy a set of criteria for the matching of pseudo- and all-electron eigenvalues and wave functions. In practice, it is also desirable that they be as smooth as possible, so that their reciprocal-space representation decays as quickly as possible. To this end, a simple modification of a standard pseudopotential generation scheme is developed. The new, smoother potentials are shown to decay significantly faster in reciprocal space, with no loss of transferability.

559 citations

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TL;DR: In this paper, the authors consider how a solid evolves during the earliest stages of growth and propose a geometric shell of atoms as a representation of the evolution process of a solid, which is referred to as geometric shell structure.

Abstract: It is interesting to consider how a solid evolves during the earliest stages of growth. The atoms reorganize into a completely new structure each time an atom is added when a cluster is very small. However, this cannot go on indefinitely. Eventually, a preferred symmetry becomes frozen into the cluster. Further growth takes place by adding layers of atoms to this frozen core. One layer is sometimes referred to as a geometric shell of atoms. Shell structure is the subject of this article.

519 citations

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TL;DR: Electronic structure of 13-atom clusters of 4d nonmagnetic solids Pd, Rh, and Ru has been studied using a linear combination of atomic orbitals molecular-orbital approach within the density functional formalism and nonzero magnetic moments are found.

Abstract: Electronic structure of 13-atom clusters of 4d nonmagnetic solids Pd, Rh, and Ru has been studied using a linear combination of atomic orbitals molecular-orbital approach within the density functional formalism. ${\mathrm{Pd}}_{13}$, ${\mathrm{Rh}}_{13}$, and ${\mathrm{Ru}}_{13}$ are all found to have nonzero magnetic moments. Unexpectedly, the ground state of ${\mathrm{Rh}}_{13}$ is found to have 21 unpaired electrons and thus a magnetic moment of 21${\mathrm{\ensuremath{\mu}}}_{\mathit{B}}$. These 4d-element magnetic moments are a result of the reduced dimensionality and the enhanced electronic degeneracy due to the symmetry of the cluster. The effect of impurities on the moments is examined through calculations on ${\mathrm{FePd}}_{12}$, ${\mathrm{FeRh}}_{12}$, ${\mathrm{RhPd}}_{12}$, and ${\mathrm{RuPd}}_{12}$ clusters.

279 citations