scholarly journals Global geometry optimization of silicon clusters described by three empirical potentials

2003 ◽  
Vol 119 (3) ◽  
pp. 1442-1450 ◽  
Author(s):  
S. Yoo ◽  
X. C. Zeng
Keyword(s):  
Geometry Optimization ◽  
Silicon Clusters ◽  
Global Geometry ◽  
Empirical Potentials

Global geometry optimization of (Ar)n and B(Ar)n clusters using a modified genetic algorithm

1996 ◽  
Vol 104 (7) ◽  
pp. 2684-2691 ◽  
Author(s):  
Susan K. Gregurick ◽  
Millard H. Alexander ◽  
Bernd Hartke
Keyword(s):  
Genetic Algorithm ◽  
Geometry Optimization ◽  
Global Geometry ◽  
Modified Genetic Algorithm

scholarly journals DNA-stabilized Ag–Au bimetallic clusters: the effects of alloying and embedding on optical properties

2016 ◽  
Vol 18 (32) ◽  
pp. 22311-22322 ◽  
Author(s):  
Dennis Palagin ◽  
Jonathan P. K. Doye
Keyword(s):  
Optical Properties ◽  
Density Functional ◽  
Geometry Optimization ◽  
Structural Evolution ◽  
Density Functional Theory Calculations ◽  
Time Dependent ◽  
Bimetallic Clusters ◽  
Functional Theory ◽  
Global Geometry ◽  
Dependent Density

Global geometry optimization and time-dependent density functional theory calculations have been used to study the structural evolution and optical properties of AgnAun (n = 2–6) nanoalloys both as individual clusters and as clusters stabilized with the fragments of DNA of different size.

scholarly journals CO oxidation catalysed by Pd-based bimetallic nanoalloys

2015 ◽  
Vol 17 (42) ◽  
pp. 28010-28021 ◽  
Author(s):  
Dennis Palagin ◽  
Jonathan P. K. Doye
Keyword(s):  
Density Functional Theory ◽  
Co Oxidation ◽  
Oxidation Reaction ◽  
Density Functional ◽  
Geometry Optimization ◽  
Energy Barriers ◽  
Functional Theory ◽  
Global Geometry ◽  
Co Oxidation Reaction

Density functional theory based global geometry optimization has been used to demonstrate the crucial influence of the geometry of the catalytic cluster on the energy barriers for the CO oxidation reaction over Pd-based bimetallic nanoalloys.

GLOBAL GEOMETRY OPTIMIZATION OF SILICON CLUSTERS EMPLOYING EMPIRICAL POTENTIALS, DENSITY FUNCTIONALS, AND AB INITIO CALCULATIONS

2005 ◽  
Vol 04 (04) ◽  
pp. 1119-1151 ◽  
Author(s):  
ADEM TEKIN ◽  
BERND HARTKE
Keyword(s):  
Ab Initio Calculations ◽  
Ab Initio ◽  
Transition Region ◽  
Basis Set ◽  
Silicon Cluster ◽  
Shape Transition ◽  
Silicon Clusters ◽  
Empirical Potentials ◽  
Cluster Shape ◽  
Spherical Structures

Si n clusters in the size range n = 4–30 have been investigated using a combination of global structure optimization methods with DFT and ab initio calculations. One of the central aims is to provide explanations for the structural transition from prolate to spherical outer shapes at about n = 25, as observed in ion mobility measurements. Firstly, several existing empirical potentials for silicon and a newly generated variant of one of them were better adapted to small silicon clusters, by global optimization of their parameters. The best resulting empirical potentials were then employed in global cluster structure optimizations. The most promising structures from this stage were relaxed further at the DFT level with the hybrid B3LYP functional. For the resulting structures, single point energies have been calculated at the LMP2 level with a reasonable medium-sized basis set, cc-pVTZ. These DFT and LMP2 calculations were also carried out for the best structures proposed in the literature, including the most recent ones, to obtain the currently best and most complete overall picture of the structural preferences of silicon clusters. In agreement with recent findings, results obtained at the DFT level do support the shape transition from prolate to spherical structures, beginning with Si 26 (albeit not completely without problems). In stark contrast, at the LMP2 level, the dominance of spherical structures after the transition region could not be confirmed. Instead, just as below the transition region, prolate isomers are obtained as the lowest-energy structures for n ≤ 29. We conclude that higher (probably multireference) levels of theoretical treatments are needed before the puzzle of the silicon cluster shape transition at n = 25 can safely be considered as explained.

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