Lowest-energy structures of cationic P2m+1+ (m=1–12) clusters from first-principles simulated annealing

2010 ◽  
Vol 485 (1-3) ◽  
pp. 26-30 ◽  
Author(s):  
Tao Xue ◽  
Jing Luo ◽  
Si Shen ◽  
Fengyu Li ◽  
Jijun Zhao
Keyword(s):  
Simulated Annealing ◽  
First Principles

A new phase in the decomposition of Mg(BH4)2: first-principles simulated annealing

2009 ◽  
Vol 19 (38) ◽  
pp. 7081 ◽  
Author(s):  
M. J. van Setten ◽  
W. Lohstroh ◽  
M. Fichtner
Keyword(s):  
Simulated Annealing ◽  
First Principles ◽  
New Phase

DETERMINATION OF THE GROUND-STATE GEOMETRIES OF COPPER CLUSTERS BY SIMULATED ANNEALING WITHIN AN EQUIVALENT CRYSTAL APPROACH

2003 ◽  
Vol 17 (03) ◽  
pp. 273-279
Author(s):  
AMITAVA BANERJEA ◽  
RADHIKA PROSAD DATTA ◽  
ABHIJIT MOOKERJEE ◽  
A. K. BHATTACHARYYA
Keyword(s):  
Simulated Annealing ◽  
First Principles ◽  
Monte Carlo Algorithm ◽  
Equilibrium Geometry ◽  
Efficient Tool ◽  
Copper Clusters ◽  
Atom Clusters ◽  
Metropolis Monte Carlo ◽  
Semi Empirical

We determine the lowest energy structures of small (11–20 atoms) copper clusters. The semi-empirical Equivalent Crystal Theory (ECT) is used in conjunction with the Metropolis Monte Carlo algorithm to determine the equilibrium geometry of each cluster via simulated annealing. The optimum structures of the clusters in this size range are found to be derived from icosahedral structures. The 13-atom cluster is an icosahedron and the 19-atom is a double-icosahedron. The other sizes show structures related to these. The 11-atom clusters, however, show somewhat different structures. We propose the ECT as an efficient tool for developing starting structures for more chemically accurate, first principles and therefore computationally very demanding, approaches.

Determination of Total Energy Tight Binding Parameters from First Principles Calculations Using Adaptive Simulated Annealing

2001 ◽  
Vol 700 ◽  
Author(s):  
Anders G. Froseth ◽  
Peter Derlet ◽  
Ragnvald Hoier
Keyword(s):  
Simulated Annealing ◽  
Total Energy ◽  
First Principles ◽  
Linear Optimization ◽  
Tight Binding ◽  
Accurate Method ◽  
Optimization Method ◽  
Binding Parameters ◽  
Non Linear

AbstractEmpirical Total Energy Tight Binding (TETB) has proven to be a fast and accurate method for calculating materials properties for various system, including bulk, surface and amorphous structures. The determination of the tight binding parameters from first-principles results is a multivariate, non-linear optimization problem with multiple local minima. Simulated annealing is an optimization method which is flexible and “guaranteed” to find a global minimum, opposed to classical methods like non-linear least squares algorithms. As an example results are presented for a nonorthogonal s,p parameterization for Silicon based on the NRL tight binding formalism.

Simulated annealing and first-principles study of substitutional Ga-doped graphene

2018 ◽  
Vol 125 (1) ◽  
Author(s):  
E. Brito ◽  
L. Leite ◽  
Sergio Azevedo ◽  
J. R. Martins ◽  
J. R. Kaschny
Keyword(s):  
Simulated Annealing ◽  
First Principles ◽  
First Principles Study ◽  
Doped Graphene

Bridging the gap – structure determination of the red polymorph of tetrahexylsexithiophene by Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement

2002 ◽  
Vol 35 (3) ◽  
pp. 296-303 ◽  
Author(s):  
Marcus A. Neumann ◽  
Consiglia Tedesco ◽  
Silvia Destri ◽  
Dino R. Ferro ◽  
William Porzio
Keyword(s):  
Crystal Structure ◽  
Monte Carlo ◽  
Simulated Annealing ◽  
Dft Calculations ◽  
Rietveld Refinement ◽  
Powder Diffraction ◽  
First Principles ◽  
Density Functional ◽  
Space Groups ◽  
Monte Carlo Simulated Annealing

The crystal structure of the red polymorph of tetrahexylsexithiophene (THST) is solved from X-ray powder diffraction data by a direct-space Monte Carlo simulated-annealing approach. First-principles density functional theory (DFT) calculations are used to distinguish between three nearly identical solutions in the space groupsC2/m,C2 andP\bar{1} and to improve the overall accuracy of the crystal structure. The correct space group is found to beC2/m. In all space groups, the thiophene backbone is planar and the hexyl side chains assume an all-transconformation except for two terminal methyl residues, which adopt agaucheorientation. The ability of first-principles DFT calculations to provide atomic coordinates of single-crystal quality is demonstrated by lattice-energy minimization of the known crystal structure of the yellow polymorph of THST. The combination of Monte Carlo simulated annealing, first-principles DFT calculations and Rietveld refinement presented in this paper is generally applicable. It provides a powerful alternative to standard approaches in cases where the information content of the powder diffraction pattern alone is insufficient to distinguish between different structure solutions. DFT calculations can also provide invaluable guidance in Rietveld refinement.

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