Difference between revisions of "SPC/E model of water"

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{{Stub-water}}
 
{{Stub-water}}
The extended simple point charge model, '''SPC/E''' is a reparameterisation  of the [[SPC]] 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 <math>q_{\mathrm{O}}</math>.
 
The molecule is modelled as
 
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 model | Lennard-Jones]] sites, situated  on the  oxygen atoms. The parameters are as follows:
 
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 model | Lennard-Jones]] sites, situated  on the  oxygen atoms. The parameters are as follows:

Revision as of 13:51, 23 May 2008

Water icon.png This article is a 'stub' about water and/or ice. It has no, or next to no, content. It is here at the moment to help form part of the structure of SklogWiki. If you add material to this article, remove the {{Stub-water}} template from this page.

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:

Water empirical1.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)
r_\mathrm{OM} 0 (charge sits on oxygen)

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

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)