Molecular simulations are becoming important sources for phase equilibrium data for a range of applications. At the same time, these methods are also becoming increasingly accessible to non-experts. As such, there is an emerging need to determine the quality of simulations using simple metrics. For vapor-liquid equilibria (VLE), the compressibility factor (<i>Z</i>) has been suggested by Ivo Nezbeda as one such metric. Here we apply the compressibility factor as a metric to the Transferable Potentials for Phase Equilibria (TraPPE) database that includes over 150 compounds with VLE data obtained from either Gibbs ensemble or grand canonical Monte Carlo simulations, and demonstrate both the strengths and limitations of this metric. Based on high-quality simulation data, we then determine numerical bounds for deviations of <i>Z</i> from expected behavior and propose a complementary metric that uses predicted vapor pressures (and their deviations) from a local fit to the Clausius-Clapeyron equation for temperature triads.

Assessing simulation quality for vapor-liquid equilibria from Gibbs-ensemble Monte Carlo

Macromolecular Chemistry: The Second Century

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ACS Spring 2020 National Meeting & Expo

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.