(272f) Coarse-Grained Lattice Monte Carlo Simulations With Continuous Interaction Potentials

Sinno, T. - Presenter, University of Pennsylvania
Liu, X., University of Pennsylvania
Seider, W., University of Pennsylvania

Various types of Monte Carlo simulations are used to simulate an enormous range of phenomena.  Restricting particle positions to fixed lattice sites can substantially increase the computational efficiency of Monte Carlo simulations, and this benefit increases as the lattice becomes coarser.  However, the confinement of particle positions to a rigid lattice necessarily reduces the available configurational degrees of freedom in a system and this constraint can become very important at elevated temperatures [1,2].  As a result, any coarse-graining approach that maps a continuous problem onto a lattice must be able to implicitly describe the influence of the missing degrees-of-freedom.

In this presentation, we discuss a new framework for performing Metropolis Monte Carlo simulations of continuous systems on coarse, rigid lattices while preserving the phase-space contributions of the missing degrees-of-freedom [3,4].  The present approach relies on the pre-computation of (approximate) discrete coarse-grained interaction potentials from standard molecular force-fields.  The coarse-grained potentials are then used to drive coarse-grained Metropolis Monte Carlo (CG-MMC) simulations of vapor-liquid systems based on Lennard-Jones, square-well, and SPC-water models.  The method accuracy, scalability, and efficiency are first demonstrated via consideration of vapor-liquid equilibria.  We then extend the CG-MMC approach to non-equilibrium situations in which diffusion and advection are both present.

[1] S. S. Kapur, M. Prasad, J. C. Crocker, T. Sinno, Role of configurational entropy in the thermodynamics of clusters of point defects in crystalline solids, Phys. Rev. B 72, 014119 (2005). 

[2] J. Dai, W. D. Seider and T. Sinno, Lattice kinetic Monte Carlo simulations of defect evolution in crystals at elevated temperature. Molecular Simulation 32, 305 (2006).

[3] X. Liu, W. Seider, and T. Sinno, Coarse-Grained Lattice Monte Carlo Simulations with Continuous Interaction Potentials, Physical Review E 86(2012) 026708 1-5.

[4] X. Liu, W. Seider, and T. Sinno, A General Method for Spatially Coarse-Graining Metropolis Monte Carlo Simulations onto a Lattice, Journal of Chemical Physics 138 (2012) 114104 1-14.