Editing SPC model of water
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The '''simple point charge''' (SPC) model | The '''simple point charge''' (SPC) model | ||
<ref>H. J. C. Berendsen, J. P. M. Postma, W. F. van Gunsteren and J. Hermans, in: Intermolecular Forces (B. Pullman, ed.), Reidel, Dordrecht (1981) | <ref>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)</ref> | ||
is an [[water models | empirical model of water]]. The molecule is modelled as | is an [[water models | empirical model of water]]. The molecule is modelled as | ||
a rigid isosceles triangle, having charges situated on each of the three atoms. | 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:Thee_site_water_model.png|center|400px]] | [[Image:Thee_site_water_model.png|center|400px]] | ||
{| border="1" | {| border="1" | ||
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| parameter || value | | parameter || value | ||
|- | |- | ||
| <math>\sigma</math> || <math> 3.166</math> | | <math>\sigma</math> || <math> 3.166 {\mathrm {\AA}}</math> | ||
|- | |- | ||
| <math>\epsilon</math> || <math>0.650</math> kJ mol<sup>-1</sup> | | <math>\epsilon</math> || <math>0.650</math> kJ mol<sup>-1</sup> | ||
|- | |- | ||
| <math>r_\mathrm{OH}</math> || <math>1.000</math> | | <math>r_\mathrm{OH}</math> || <math>1.000\mathrm{\AA}</math> | ||
|- | |- | ||
| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | | <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | ||
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| <math>q_{\mathrm{O}}</math> || <math>-0.82 e</math> | | <math>q_{\mathrm{O}}</math> || <math>-0.82 e</math> | ||
|- | |- | ||
| <math>q_{\mathrm{H}}</math> || <math> | | <math>q_{\mathrm{H}}</math> || <math>q_{\mathrm{O}}/2</math> (charge neutrality) | ||
|} | |} | ||
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==Surface tension== | ==Surface tension== | ||
The [[surface tension]] has been studied for the SPC model by Vega and Miguel. | The [[surface tension]] has been studied for the SPC model by Vega and Miguel. | ||
*[http://dx.doi.org/10.1063/1.2715577 C. Vega and E. de Miguel "Surface tension of the most popular models of water by using the test-area simulation method", Journal of Chemical Physics '''126''' 154707 (2007)] | |||
==Related models== | ==Related models== | ||
Over the years a number of variants of the SPC model have been published: | Over the years a number of variants of the SPC model have been published: | ||
*[[SPC | *[[SPC]] | ||
*[[SPC/E]] | *[[SPC/E]] | ||
*[[SPC/F]] | *[[SPC/F]] | ||
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*[[SPC/Fw]] | *[[SPC/Fw]] | ||
*[[SPC/HW]] | *[[SPC/HW]] | ||
*[[SPCP]] | *[[SPCP]] | ||
*[[SPC-pol]] | *[[SPC-pol]] | ||
==References== | ==References== | ||
<references/> | <references/> | ||
[[category: water]] | [[category: water]] | ||
[[category: models]] | [[category: models]] |