SPC model of water: Difference between revisions

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The '''simple point charge''' (SPC) model
The '''simple point charge''' (SPC) model
UNIQ3c9329b265030360-ref-00000015-QINU
<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) p. 331 ISBN 902771326X</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. As well as [[Coulomb's law |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. As well as [[Coulomb's law |Coulombic interactions]], the molecules interact via long-range [[Lennard-Jones model | Lennard-Jones]] sites, situated  on the  oxygen atoms. The parameters are as follows:
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| parameter || value
| parameter || value
|-   
|-   
| UNIQ3c9329b265030360-math-00000016-QINU || UNIQ3c9329b265030360-math-00000017-QINU&#8491;
| <math>\sigma</math> || <math> 3.166</math>&#8491;
|-
|-
| UNIQ3c9329b265030360-math-00000018-QINU || UNIQ3c9329b265030360-math-00000019-QINU kJ mol<sup>-1</sup>
| <math>\epsilon</math> || <math>0.650</math> kJ mol<sup>-1</sup>
|-
|-
| UNIQ3c9329b265030360-math-0000001A-QINU || UNIQ3c9329b265030360-math-0000001B-QINU&#8491;
| <math>r_\mathrm{OH}</math> || <math>1.000</math>&#8491;
|-
|-
| UNIQ3c9329b265030360-math-0000001C-QINU || UNIQ3c9329b265030360-math-0000001D-QINU
| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math>
|-
|-
| UNIQ3c9329b265030360-math-0000001E-QINU ||  UNIQ3c9329b265030360-math-0000001F-QINU
| <math>q_{\mathrm{O}}</math> ||  <math>-0.82 e</math>
|-
|-
| UNIQ3c9329b265030360-math-00000020-QINU ||  UNIQ3c9329b265030360-math-00000021-QINU (charge neutrality)
| <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.
UNIQ3c9329b265030360-ref-00000022-QINU
<ref>[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)]</ref>
==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/&epsilon; water model | SPC/&epsilon;]]
*[[SPC/A]]
*[[SPC/E]]
*[[SPC/E]]
*[[SPC/F]]
*[[SPC/F]]
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*[[SPC/Fw]]
*[[SPC/Fw]]
*[[SPC/HW]]
*[[SPC/HW]]
*[[SPC/L]]
*[[SPCP]]
*[[SPCP]]
*[[SPC-pol]]
*[[SPC-pol]]
==References==
==References==
UNIQ3c9329b265030360-references-00000023-QINU
<references/>
[[category: water]]
[[category: water]]
[[category: models]]
[[category: models]]

Latest revision as of 14:20, 9 February 2015

The simple point charge (SPC) model [1] is an empirical model of water. The molecule is modelled as a rigid isosceles triangle, having charges situated on each of the three atoms. As well as Coulombic interactions, the molecules interact via long-range Lennard-Jones sites, situated on the oxygen atoms. The parameters are as follows:

parameter value
σ 3.166Å
ϵ 0.650 kJ mol-1
rOH 1.000Å
∠HOH 109.47∘
qO −0.82e
qH |qO|/2 (charge neutrality)

The SPC model has a dipole moment of 2.27 D.

Surface tension[edit]

The surface tension has been studied for the SPC model by Vega and Miguel. [2]

Related models[edit]

Over the years a number of variants of the SPC model have been published:

References[edit]

  1. ↑ H. J. C. Berendsen, J. P. M. Postma, W. F. van Gunsteren and J. Hermans, in: Intermolecular Forces (B. Pullman, ed.), Reidel, Dordrecht (1981) p. 331 ISBN 902771326X
  2. ↑ 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)