Simulation of Equilibrated States via Molecular Monte Carlo Method of Systems Connected to 3 Reservoirs

Abstract: Metastable structures in macromolecular and colloidal systems are non-equilibrium states that often have long lifetimes and cause difficulties in simulating equilibrium. In order to escape from the long-lived metastable states, we propose a newly devised method, molecular Monte-Carlo simulation of systems connected to 3 reservoirs: chemical potential $\mu$, pressure $P$, and temperature $T$. One of these reservoirs is adjusted for the thermodynamic equilibrium condition according to Gibbs-Duhem equation, so that this adjusted 3rd reservoir does not thermodynamically affect phases and states. Additional degrees of freedom, i.e. system volume $V$ and the number of particles $N$, reduce kinetic barriers of non-equilibrium states and facilitate quick equilibration. We show globally-anisotropic defect-free ordered structures, e.g. string-like colloidal assembly, are obtained via our method.