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Single string based global optimizer for geometry optimization in strongly coupled finite clusters: An adaptive mutation-driven strategy

DSpace at IIT Bombay

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Title Single string based global optimizer for geometry optimization in strongly coupled finite clusters: An adaptive mutation-driven strategy
 
Creator SARKAR, K
BHATTACHARYYA, SP
 
Subject LENNARD-JONES CLUSTERS
GENETIC ALGORITHM
COULOMB CLUSTERS
CRYSTAL
MINIMUM
PLASMAS
SEARCH
PHASE
 
Description We propose and implement a simple adaptive heuristic to optimize the geometries of clusters of point charges or ions with the ability to find the global minimum energy configurations. The approach uses random mutations of a single string encoding the geometry and accepts moves that decrease the energy. Mutation probability and mutation intensity are allowed to evolve adaptively on the basis of continuous evaluation of past explorations. The resulting algorithm has been called Completely Adaptive Random Mutation Hill Climbing method. We have implemented this method to search through the complex potential energy landscapes of parabolically confined 3D classical Coulomb clusters of hundreds or thousands of charges-usually found in high frequency discharge plasmas. The energy per particle (E-N/N) and its first and second differences, structural features, distribution of the oscillation frequencies of normal modes, etc., are analyzed as functions of confinement strength and the number of charges in the system. Certain magic numbers are identified. In order to test the feasibility of the algorithm in cluster geometry optimization on more complex energy landscapes, we have applied the algorithm for optimizing the geometries of MgO clusters, described by Coulomb-Born-Mayer potential and finding global minimum of some Lennard-Jones clusters. The convergence behavior of the algorithm compares favorably with those of other existing global optimizers. (C) 2013 AIP Publishing LLC.
 
Publisher AMER INST PHYSICS
 
Date 2014-10-15T10:24:23Z
2014-10-15T10:24:23Z
2013
 
Type Article
 
Identifier JOURNAL OF CHEMICAL PHYSICS, 139(7)
http://dx.doi.org/10.1063/1.4818162
http://dspace.library.iitb.ac.in/jspui/handle/100/14738
 
Language en