Difference between revisions of "SPC model of water"

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{{Stub-water}}
 
{{Stub-water}}
The '''simple point charge''' empirical [[models |model]] (SPC) of [[water]]. The molecule is modelled as
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The '''simple point charge''' (SPC) model is an [[Empirical water models | empirical model of water]]. The molecule is modelled as
a rigid isosceles triangle, with charge sites at each of the three atoms. Apart from Coulomb interactions, the molecules interact via long-range [[Lennard-Jones model | Lennard-Jones]] sites only at Oxygen atoms. The parameters are as follows:
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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:
 
[[Image:Water_empirical1.png|center|300px]]
 
[[Image:Water_empirical1.png|center|300px]]
 
{| border="1"
 
{| border="1"
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| <math>q_{\mathrm{H}}</math> ||  <math>q_{\mathrm{O}}/2</math> (charge neutrality)
 
| <math>q_{\mathrm{H}}</math> ||  <math>q_{\mathrm{O}}/2</math> (charge neutrality)
 
|-
 
|-
| <math>r_\mathrm{OM}</math> ||  <math>0</math> (charge sits on Oxygen)
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| <math>r_\mathrm{OM}</math> ||  <math>0</math> (charge sits on oxygen)
 
|}
 
|}
  

Revision as of 12:18, 15 February 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 simple point charge (SPC) model is an empirical model of water. 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}} -0.82 e
q_{\mathrm{H}} q_{\mathrm{O}}/2 (charge neutrality)
r_\mathrm{OM} 0 (charge sits on oxygen)


References

  1. H. J. C. Berendsen, J. P. M. Postma, W. F. van Gunsteren and J. Hermans, in: Intermolecular Forces (B. Pullman, ed.), Reidel, Dordrecht, p. 331 (1981).