Bulletin of the American Physical Society
APS March Meeting 2018
Monday–Friday, March 5–9, 2018; Los Angeles, California
Session B38: Advances in Computational Statistical Mechanics and their Applications: Part 2
11:15 AM–2:15 PM,
Monday, March 5, 2018
LACC Room: 501A
Sponsoring Units: DCOMP DCMP GSNP
Chair: Ying Wai Li, Oak Ridge National Lab
Abstract: B38.00002 : Phase diagrams of complex systems with nested sampling*
11:51 AM–12:03 PM
(Naval Research Lab)
(Naval Research Lab)
K. Michael Salerno
(National Research Council)
(Engineering Dept., Cambridge University)
The nested sampling method provides an efficient way of computing the classical partition function, and from it thermodynamic quantities and other observables as a function of temperature and pressure. It can therefore be used to calculate temperature dependent properties and phase diagrams. We show how nested sampling can be applied to two systems with chemical and structural complexity. The first is polymers, which have both short range (bond length, angle) and long range (conformation, dense packing in the melt/solid) structure, which we model with chemicaly specific coarse-grained potentials. We show how to explore configuration space given the form of typical coarse-grained models, and present results for their phase diagrams. The second is multicomponent systems, which can exhibit phase separation in some parts of the phase diagram, e.g. a two-phase coexistence region delimited by a liquidus at high T and solidus at low T for the liquid-solid transition in a binary alloy. We discuss several approaches to handling this tendency to phase separation, and demonstrate that we can efficiently compute phase diagrams for multicomponent systems.
*NB was supported by ONR through the U. S. NRL's core basic research program. KMS was supported by a NRC associateship at the U. S. NRL.
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