SPC/E model of water

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The extended simple point charge model, SPC/E is a slight reparameterisation of the SPC model of water, with a modified value for q_{\mathrm{O}}. The molecule is modelled as a rigid isosceles triangle, having charges situated on each of the three atoms. Apart from Coulombic interactions, the molecules interact via long-range Lennard-Jones sites, situated on the oxygen atoms. The parameters are as follows:

Thee site water model.png
parameter value
\sigma  3.166 {\mathrm {\AA}}
\epsilon 0.650 kJ mol-1
r_\mathrm{OH} 1.000\mathrm{\AA}
\angle_\mathrm{HOH} 109.47^{\circ}
q_{\mathrm{O}} -0.8476 e
q_{\mathrm{H}} q_{\mathrm{O}}/2 (charge neutrality)

The SPC/E model has a dipole moment of 2.351 D. (Ref. 1 Table I).

Surface tension

The surface tension has been studied for the SPC/E model by Vega and Miguel.

Phase diagram

SPC E phase diagram.png

Plastic crystal phases

Recent simulations have demonstrated the existence of plastic crystal phases for the SPC/E model.

Shear viscosity

The shear viscosity for the SPC/E model is 0.729 mPa.s at 298 K and 1 bar [1] (experimental value 0.896 mPa.s [2]).

References

  1. H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma "The missing term in effective pair potentials", Journal of Physical Chemistry 91 pp. 6269 - 6271 (1987)
  2. Swaroop Chatterjee, Pablo G. Debenedetti, Frank H. Stillinger, and Ruth M. Lynden-Bell "A computational investigation of thermodynamics, structure, dynamics and solvation behavior in modified water models", Journal of Chemical Physics 128 124511 (2008)
    1. Miguel Angel González and José L. F. Abascal "The shear viscosity of rigid water models", Journal of Chemical Physics 132 096101 (2010)
    2. Kenneth R. Harris and Lawrence A. Woolf "Temperature and Volume Dependence of the Viscosity of Water and Heavy Water at Low Temperatures", Journal of Chemical & Engineering Data 49 pp. 1064-1069 (2004)
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