Dresden 2006 – scientific programme
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CPP: Chemische Physik und Polymerphysik
CPP 29: Computational Techniques
CPP 29.2: Talk
Friday, March 31, 2006, 10:45–11:00, ZEU 160
Modeling multi-body effects in ionic solutions with a concentration dependent dielectric permittivity — •Berk hess1, Christian Holm2,1, and Nico van der Vegt1 — 1Max-Planck Institute for Polymer Research, Ackermannweg 10, D-55128 Mainz, Germany — 2Frankfurt Institute for Advanced Study (FIAS), J.W. Goethe Universität, Max-von-Laue Strasse 1, D-60438 Frankfurt/Main, Germany
We report a new strategy to parameterize effective ion-ion potentials for large-scale implicit solvent simulations of charge systems. The effective potential includes a pair term, derived from explicit solvent simulation of a single ion pair, and a Coulomb term that by means of a concentration dependent dielectric permittivity takes into account all multi-body effects. We show that, for aqueous NaCl as an example system, this approach allows to accurately predict the solution osmotic properties up to concentrations of 2.8 molar salt. Replacing the pair term with a Weeks-Chandler-Andersen potential leads to equally good predictions, which indicates that ion-specific hydration effects featuring in the effective potential need not be included. The use of a concentration dependent dielectric permittivity opens new ways to study systems with inhomogeneous charges distributions.