Systematic comparison of force fields for microscopic simulations of NaCl in aqueous solutions: Diffusion, free energy of hydration, and structural properties

Authors

  • Michael Patra,

    Corresponding author
    1. Biophysics and Statistical Mechanics Group, Laboratory for Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FIN-02015 HUT, Finland
    • Biophysics and Statistical Mechanics Group, Laboratory for Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FIN-02015 HUT, Finland
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  • Mikko Karttunen

    1. Biophysics and Statistical Mechanics Group, Laboratory for Computational Engineering, Helsinki University of Technology, P.O. Box 9203, FIN-02015 HUT, Finland
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Abstract

In this article we compare different force fields that are widely used (Gromacs, Charmm-22/x-Plor, Charmm-27, Amber-1999, OPLS-AA) in biophysical simulations containing aqueous NaCl. We show that the uncertainties of the microscopic parameters of, in particular, sodium, and, to a lesser extent, chloride, translate into large differences in the computed radial-distribution functions. This uncertainty reflect the incomplete experimental knowledge of the structural properties of ionic aqueous solutions at finite molarity. We discuss possible implications on the computation of potential of mean force and effective potentials. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 678–689, 2004

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