A comparison of effective and polarizable intermolecular potentials in simulations: liquid water as a test case |
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Authors: | THOMAS M. NYMAND PER LINSE PER-OLOF ÅSTRAND |
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Affiliation: | 1. Department of Chemistry , Aarhus University , DK-8000, ?rhus C, Denmark;2. Physical Chemistry 1, Center for Chemistry and Chemical Engineering , Lund University , S-221 00, Lund, Sweden;3. Condensed Matter Physics and Chemistry Department, Ri? National Laboratory , DK-4000, Roskilde, Denmark |
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Abstract: | A comparison of polarizable and effective intermolecular potentials has been carried out by employing simulated properties of liquid water at different temperatures. The effective potentials were obtained by adding a fixed fraction (~80%) of the induced dipole moments of the polarizable potential to the permanent dipole moment of the water molecule. The fraction was fitted to reproduce one structural (the height of the first peak of the oxygen-oxygen radial distribution function) and one dynamic (the self-diffusion coefficient) liquid property predicted by the polarizable potential. The two properties were well reproduced simultaneously by the effective potential at 273 K and 303 K, but less accurately at 373 K. The effective dipole moments were 2.79, 2.75, and 2.68 D at the three respective temperatures. In order to examine the effective potentials further, other liquid properties have been considered, and we found that the molecular rotational relaxation times and the hydrogen bonding properties are reproduced well by the effective potentials, whereas the velocity autocorrelation function, the pressure, the dielectric constant, and the Debye relaxation time are reproduced less accurately. |
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