Absolute hydration free energy scale for alkali and halide ions established from simulations with a polarizable force field

Guillaume Lamoureux, Benoît Roux

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306 Scopus citations

Abstract

A polarizable potential function for the hydration of alkali and halide ions is developed on the basis of the recent SWM4-DP water model [Lamoureux, G.; MacKerell, A. D., Jr.; Roux, B. J. Chem. Phys. 2003, 119, 5185]. Induced polarization is incorporated using classical Drude oscillators that are treated as auxiliary dynamical degrees of freedom. The ions are represented as polarizable Lennard-Jones centers, whose parameters are optimized to reproduce the binding energies of gas-phase monohydrates and the hydration free energies in the bulk liquid. Systematic exploration of the parameters shows that the monohydrate binding energies can be consistent with a unique hydration free energy scale if the computed hydration free energies incorporate the contribution from the air/water interfacial electrostatic potential (-540 mV for SWM4-DP). The final model, which can satisfyingly reproduce both gas and bulk-phase properties, corresponds to an absolute scale in which the intrinsic hydration free energy of the proton is -247 kcal/mol.

Original languageEnglish (US)
Pages (from-to)3308-3322
Number of pages15
JournalJournal of Physical Chemistry B
Volume110
Issue number7
DOIs
StatePublished - Feb 23 2006
Externally publishedYes

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Surfaces, Coatings and Films
  • Materials Chemistry

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