LMU München
Fakultät für Physik



(c) 2002 BMO

"Angular resolution and range of dipole-dipole correlations in water"
Gerald Mathias and Paul Tavan
J. Chem. Phys. 120, 4393-4403 (2004)

We investigate the dipolar correlations in liquid water at angular resolution by molecular-dynamics (MD) simulations of a large periodic simulation system containing about 40,000 molecules. Because we are particularly interested in the long-range ordering, we use a simple three point model for these molecules. The electrostatics is treated both by Ewald summation and by minimum image truncation combined with a reaction field approach. To gain insight into the angular dependence of the simulated dipolar ordering we introduce a suitable expansion of the molecular pair distribution function into a set of two-dimensional correlation functions. We show that these functions enable detailed insights into the shell structure of the dipolar ordering around a given water molecule. For these functions we derive analytical expressions in the particular case, in which liquid water is conceived as a dielectric continuum. Comparisons of these continuum models with the correlation functions derived from the simulations yield the key result that liquid water behaves like a continuum dielectric beyond distances of about 15 Å from a given water molecule. We argue that this should be a generic property of water independent of our modeling. By comparison of the results of the two different electrostatics treatments with the continuum description we show that the boundary artifacts occurring in both methods are isotropically distributed and are locally small in the respective boundary regions.

BMO authors (in alphabetic order):
Gerald Mathias
Paul Tavan

Assoziierte Projekte:
Long-range electrostatics in molecular dynamics simulations

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Letzte Änderung: 2016-09-14 11:34