Minimal Energy Configurations of Finite Molecular Arrays

In this paper, we consider the problem of characterizing the minimum energy configurations of a finite system of particles interacting between them due to attractive or repulsive forces given by a certain intermolecular potential. We limit ourselves to the cases of three particles arranged in a tria...

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Main Authors: Pablo V. Negrón-Marrero, Melissa López-Serrano
Format: Article
Language:English
Published: MDPI AG 2019-01-01
Series:Symmetry
Subjects:
Online Access:https://www.mdpi.com/2073-8994/11/2/158
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author Pablo V. Negrón-Marrero
Melissa López-Serrano
author_facet Pablo V. Negrón-Marrero
Melissa López-Serrano
author_sort Pablo V. Negrón-Marrero
collection DOAJ
description In this paper, we consider the problem of characterizing the minimum energy configurations of a finite system of particles interacting between them due to attractive or repulsive forces given by a certain intermolecular potential. We limit ourselves to the cases of three particles arranged in a triangular array and that of four particles in a tetrahedral array. The minimization is constrained to a fixed area in the case of the triangular array, and to a fixed volume in the tetrahedral case. For a general class of intermolecular potentials we give conditions for the homogeneous configuration (either an equilateral triangle or a regular tetrahedron) of the array to be stable that is, a minimizer of the potential energy of the system. To determine whether or not there exist other stable states, the system of first-order necessary conditions for a minimum is treated as a bifurcation problem with the area or volume variable as the bifurcation parameter. Because of the symmetries present in our problem, we can apply the techniques of equivariant bifurcation theory to show that there exist branches of non-homogeneous solutions bifurcating from the trivial branch of homogeneous solutions at precisely the values of the parameter of area or volume for which the homogeneous configuration changes stability. For the triangular array, we construct numerically the bifurcation diagrams for both a Lennard⁻Jones and Buckingham potentials. The numerics show that there exist non-homogeneous stable states, multiple stable states for intervals of values of the area parameter, and secondary bifurcations as well.
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spelling doaj.art-5a9dd40a82ac4465911c318fe4d92afc2022-12-22T03:19:19ZengMDPI AGSymmetry2073-89942019-01-0111215810.3390/sym11020158sym11020158Minimal Energy Configurations of Finite Molecular ArraysPablo V. Negrón-Marrero0Melissa López-Serrano1Department of Mathematics, University of Puerto Rico, Humacao, PR 00791-4300, USADepartment of Mathematics, University of Puerto Rico, Humacao, PR 00791-4300, USAIn this paper, we consider the problem of characterizing the minimum energy configurations of a finite system of particles interacting between them due to attractive or repulsive forces given by a certain intermolecular potential. We limit ourselves to the cases of three particles arranged in a triangular array and that of four particles in a tetrahedral array. The minimization is constrained to a fixed area in the case of the triangular array, and to a fixed volume in the tetrahedral case. For a general class of intermolecular potentials we give conditions for the homogeneous configuration (either an equilateral triangle or a regular tetrahedron) of the array to be stable that is, a minimizer of the potential energy of the system. To determine whether or not there exist other stable states, the system of first-order necessary conditions for a minimum is treated as a bifurcation problem with the area or volume variable as the bifurcation parameter. Because of the symmetries present in our problem, we can apply the techniques of equivariant bifurcation theory to show that there exist branches of non-homogeneous solutions bifurcating from the trivial branch of homogeneous solutions at precisely the values of the parameter of area or volume for which the homogeneous configuration changes stability. For the triangular array, we construct numerically the bifurcation diagrams for both a Lennard⁻Jones and Buckingham potentials. The numerics show that there exist non-homogeneous stable states, multiple stable states for intervals of values of the area parameter, and secondary bifurcations as well.https://www.mdpi.com/2073-8994/11/2/158molecular arraysconstrained optimizationequivariant bifurcation theory
spellingShingle Pablo V. Negrón-Marrero
Melissa López-Serrano
Minimal Energy Configurations of Finite Molecular Arrays
Symmetry
molecular arrays
constrained optimization
equivariant bifurcation theory
title Minimal Energy Configurations of Finite Molecular Arrays
title_full Minimal Energy Configurations of Finite Molecular Arrays
title_fullStr Minimal Energy Configurations of Finite Molecular Arrays
title_full_unstemmed Minimal Energy Configurations of Finite Molecular Arrays
title_short Minimal Energy Configurations of Finite Molecular Arrays
title_sort minimal energy configurations of finite molecular arrays
topic molecular arrays
constrained optimization
equivariant bifurcation theory
url https://www.mdpi.com/2073-8994/11/2/158
work_keys_str_mv AT pablovnegronmarrero minimalenergyconfigurationsoffinitemoleculararrays
AT melissalopezserrano minimalenergyconfigurationsoffinitemoleculararrays