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Leveraging Gibbs Ensemble Molecular Dynamics and Hybrid Monte Carlo/Molecular Dynamics for Efficient Study of Phase Equilibria
journal contribution
posted on 2016-09-29, 00:00 authored by Thomas
E. Gartner, Thomas H. Epps, Arthi JayaramanWe describe an extension
of the Gibbs ensemble molecular dynamics
(GEMD) method for studying phase equilibria. Our modifications to
GEMD allow for direct control over particle transfer between phases
and improve the method’s numerical stability. Additionally,
we found that the modified GEMD approach had advantages in computational
efficiency in comparison to a hybrid Monte Carlo (MC)/MD Gibbs ensemble
scheme in the context of the single component Lennard-Jones fluid.
We note that this increase in computational efficiency does not compromise
the close agreement of phase equilibrium results between the two methods.
However, numerical instabilities in the GEMD scheme hamper GEMD’s
use near the critical point. We propose that the computationally efficient
GEMD simulations can be used to map out the majority of the phase
window, with hybrid MC/MD used as a follow up for conditions under
which GEMD may be unstable (e.g., near-critical behavior). In this
manner, we can capitalize on the contrasting strengths of these two
methods to enable the efficient study of phase equilibria for systems
that present challenges for a purely stochastic GEMC method, such
as dense or low temperature systems, and/or those with complex molecular
topologies.