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Temperature extrapolation of multicomponent grand canonical free energy landscapes

Published

Author(s)

Nathan Mahynski, Jeffrey R. Errington, Vincent K. Shen

Abstract

We derive a method for extrapolating the grand canonical free energy landscape of a multicomponent fluid system from one temperature to another. Previously, we introduced this statistical mechanical framework for the case where kinetic energy contributions to the classical partition function were neglected for simplicity [Mahynski et al., J. Chem. Phys. 146, 074101 (2017)]. Here, we generalize the derivation to admit these contributions in order to explicitly illustrate the differences which result. Specifically, we show how factoring out kinetic energy effects a priori, in order to consider only the configurational partition function, leads to simpler mathematical expressions which tend to produce more accurate extrapolations than when these effects are included. We demonstrate this by comparing and contrasting these two approaches for the simple cases of an ideal gas and a non-ideal, square-well fluid.
Citation
The Journal of Chemical Physics

Keywords

Monte Carlo simulation, Multicomponent fluid, Low temperature, Free energy, Kinetic energy

Citation

Mahynski, N. , Errington, J. and Shen, V. (2017), Temperature extrapolation of multicomponent grand canonical free energy landscapes, The Journal of Chemical Physics, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=923163 (Accessed July 31, 2021)
Created August 7, 2017, Updated December 26, 2017