Free energy reconstruction from steered dynamics without post-processing

Journal Article · Mon Sep 20 00:00:00 EDT 2010 · Journal of Computational Physics

DOI:https://doi.org/10.1016/j.jcp.2010.06.003· OSTI ID:21417247

Athenes, Manuel ^[1]; Marinica, Mihai-Cosmin ^[1]

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1. Service de Recherches de Metallurgie Physique, Departement des Materiaux pour le Nucleaire, CEA Saclay, F-91191 Gif-sur-Yvette (France)

Various methods achieving importance sampling in ensembles of nonequilibrium trajectories enable one to estimate free energy differences and, by maximum-likelihood post-processing, to reconstruct free energy landscapes. Here, based on Bayes theorem, we propose a more direct method in which a posterior likelihood function is used both to construct the steered dynamics and to infer the contribution to equilibrium of all the sampled states. The method is implemented with two steering schedules. First, using non-autonomous steering, we calculate the migration barrier of the vacancy in Fe-{alpha}. Second, using an autonomous scheduling related to metadynamics and equivalent to temperature-accelerated molecular dynamics, we accurately reconstruct the two-dimensional free energy landscape of the 38-atom Lennard-Jones cluster as a function of an orientational bond-order parameter and energy, down to the solid-solid structural transition temperature of the cluster and without maximum-likelihood post-processing.

• OSTI ID: 21417247
• Journal Information: Journal of Computational Physics, Vol. 229, Issue 19; Other Information: DOI: 10.1016/j.jcp.2010.06.003; PII: S0021-9991(10)00317-7; Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; ISSN 0021-9991
• Country of Publication: United States
• Language: English

Related Subjects

97 MATHEMATICAL METHODS AND COMPUTING
COMPUTERIZED SIMULATION
EQUILIBRIUM
FREE ENERGY
FUNCTIONS
MAXIMUM-LIKELIHOOD FIT
MOLECULAR DYNAMICS METHOD
MONTE CARLO METHOD
ORDER PARAMETERS
THERMODYNAMICS
TRANSITION TEMPERATURE
TWO-DIMENSIONAL CALCULATIONS
VACANCIES
CALCULATION METHODS
CRYSTAL DEFECTS
CRYSTAL STRUCTURE
DIMENSIONLESS NUMBERS
ENERGY
MATHEMATICAL SOLUTIONS
NUMERICAL SOLUTION
PHYSICAL PROPERTIES
POINT DEFECTS
SIMULATION
THERMODYNAMIC PROPERTIES