Ground State Structure of Cu Nanoclusters

2011 ◽  
Author(s):  
Y. H. Park ◽  
I. Hijazi
Keyword(s):  
Monte Carlo ◽  
Ground State ◽  
Building Blocks ◽  
Noble Metal Nanoparticles ◽  
Ground State Structure ◽  
State Structure ◽  
Embedded Atom ◽  
The Monte Carlo Method ◽  
Monte Carlo Simulated Annealing ◽  
Eam Potential

The study of metal clusters has attracted much attention in recent years. Noble metal nanoparticles are of particular interest since their chemical, thermodynamic, electronic, and optical properties make them interesting candidates as building blocks of nanostructure materials. Delineation of these properties requires a complete and definitive characterization of the cluster’s geometrical structure. To find the ground state structure for a cluster, the potential-energy surface (PES) needs to be searched. In this paper, we proposed an efficient hierarchical search method to determine a ground state structure of copper clusters using an effective Monte Carlo simulated annealing method, which employs the Aggregate-Volume-Bias Monte Carlo (AVBMC) algorithm. Incorporated in the Monte Carlo method, is an efficient Embedded Atom Method (EAM) potential developed by the authors.

Determination of Transitional Size of Metal Clusters

2013 ◽  
Author(s):  
Y. H. Park ◽  
I. Hijazi
Keyword(s):  
Monte Carlo ◽  
Size Effect ◽  
Ground State ◽  
Global Minimum ◽  
Metal Clusters ◽  
Critical Size ◽  
Empirical Method ◽  
Ground State Structure ◽  
State Structure ◽  
Eam Potential

We investigated the transitional size of metal clusters where the electronic effect and the size effect on the ground state structure become weaker. Identification of a transitional size cluster provides the means to efficiently determine the ground state structure of large clusters using density functional theory. Beyond the critical size of clusters, geometrical effects become important and the putative global minimum obtained from an empirical method can be used to determine the true ground state structure where the size effect on structures is less significant. We identified the lowest-energy structure using a first principles method in combination with the global search algorithm. We then used the similarity function to quantify structural difference and similarity between the global minimum obtained from an empirical method and the true ground state structure. Two structures become similar beyond a certain critical size. To investigate low-lying structures of metal clusters, we used a Monte Carlo simulated annealing method which employs the Aggregate-Volume-Bias Monte Carlo (AVBMC) algorithm. Incorporated in the Monte Carlo method is an Embedded Atom Method (EAM) potential developed by the authors.

Monte Carlo Simulation for Structure of Metallic Clusters

2010 ◽  
Author(s):  
Y. H. Park ◽  
I. Hijazi
Keyword(s):  
Monte Carlo ◽  
Empirical Studies ◽  
Gold Clusters ◽  
Structural Motif ◽  
Pentagonal Bipyramid ◽  
Embedded Atom Method ◽  
Embedded Atom ◽  
The Monte Carlo Method ◽  
Monte Carlo Simulated Annealing ◽  
Eam Potential

The structural stability and energetics for small copper and gold clusters Cun and Aun (n = 21–56) were investigated using an effective Monte Carlo simulated annealing method, which employs the Aggregate-Volume-Bias Monte Carlo (AVBMC) algorithm. Incorporated in the Monte Carlo method, is an efficient Embedded Atom Method (EAM) potential developed by the authors. In general agreement with previous empirical studies, the lowest-energy copper structures adapt a single icosahedral structural motif, with pentagonal bipyramid geometry as the building block. However, contrary to studies that describe gold as less symmetric, this work demonstrates that gold clusters adapt both an icosahedral and icositetrahedral structural motifs with many clusters having symmetric geometries.

Electronic Absorption and Ground State Structure of Carotenoid Molecules

2013 ◽  
Vol 117 (38) ◽  
pp. 11015-11021 ◽  
Author(s):  
Maria M. Mendes-Pinto ◽  
Elodie Sansiaume ◽  
Hideki Hashimoto ◽  
Andrew A. Pascal ◽  
Andrew Gall ◽  
...  
Keyword(s):  
Electronic Absorption ◽  
Ground State ◽  
Ground State Structure ◽  
State Structure

scholarly journals FIELD DECOMPOSITION AND THE GROUND STATE STRUCTURE OF SU(2) YANG–MILLS THEORY

2002 ◽  
Vol 17 (25) ◽  
pp. 3681-3688 ◽  
Author(s):  
LISA FREYHULT
Keyword(s):  
Effective Potential ◽  
Ground State ◽  
Scalar Fields ◽  
Background Field ◽  
Field Method ◽  
Gauge Fields ◽  
Ground State Structure ◽  
State Structure ◽  
Yang Mills ◽  
Background Field Method

We compute the effective potential of SU(2) Yang–Mills theory using the background field method and the Faddeev–Niemi decomposition of the gauge fields. In particular, we find that the potential will depend on the values of two scalar fields in the decomposition and that its structure will give rise to a symmetry breaking.

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