Comparative atomistic and coarse-grained study of water: What do we lose by coarse-graining?
Max Planck Institute for Polymer Research, Ackermannweg 10, D-55128, Mainz, Germany
2 LMAM and School of Mathematical Sciences, Peking University, 100871, Beijing, PRC
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Revised: 5 December 2008
Published online: 14 January 2009
We employ the inverse Boltzmann method to coarse-grain three commonly used three-site water models (TIP3P, SPC and SPC/E) where one molecule is replaced with one coarse-grained particle with isotropic two-body interactions only. The shape of the coarse-grained potentials is dominated by the ratio of two lengths, which can be rationalized by the geometric constraints of the water clusters. It is shown that for simple two-body potentials either the radial distribution function or the geometrical packing can be optimized. In a similar way, as needed for multiscale methods, either the pressure or the compressibility can be fitted to the all atom liquid. In total, a speed-up by a factor of about 50 in computational time can be reached by this coarse-graining procedure.
PACS: 05.10.-a Computational methods in statistical physics and nonlinear dynamics – / 61.20.Ja Computer simulation of liquid structure – / 65.20.Jk Studies of thermodynamic properties of specific liquids –
© EDP Sciences, SIF, Springer-Verlag Berlin Heidelberg, 2009