# Difference between revisions of "SPC model of water"

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− | + | The '''simple point charge''' (SPC) model | |

− | The '''simple point charge''' (SPC) model is an [[ | + | <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> |

− | a rigid isosceles triangle, having charges situated on each of the three atoms. | + | is an [[water models | empirical model of water]]. The molecule is modelled as |

− | [[Image: | + | 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: |

+ | [[Image:Thee_site_water_model.png|center|400px]] | ||

{| border="1" | {| border="1" | ||

|- | |- | ||

| parameter || value | | parameter || value | ||

|- | |- | ||

− | | <math>\sigma</math> || <math> 3.166 | + | | <math>\sigma</math> || <math> 3.166</math>Å |

|- | |- | ||

| <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>r_\mathrm{OH}</math> || <math>1.000</math>Å |

|- | |- | ||

| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | | <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math> | ||

Line 17: | Line 18: | ||

| <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>q_{\mathrm{O}}/2</math> (charge neutrality | + | | <math>q_{\mathrm{H}}</math> || <math>|q_{\mathrm{O}}|/2</math> (charge neutrality) |

− | |||

− | |||

|} | |} | ||

The SPC model has a [[dipole moment]] of 2.27 D. | The SPC model has a [[dipole moment]] of 2.27 D. | ||

− | + | ==Surface tension== | |

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

+ | <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== | ||

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

+ | *[[SPC/ε water model | SPC/ε]] | ||

+ | *[[SPC/A]] | ||

+ | *[[SPC/E]] | ||

+ | *[[SPC/F]] | ||

+ | *[[SPC/F2]] | ||

+ | *[[SPC/FP]] | ||

+ | *[[SPC/FQ]] | ||

+ | *[[SPC/Fw]] | ||

+ | *[[SPC/HW]] | ||

+ | *[[SPC/L]] | ||

+ | *[[SPCP]] | ||

+ | *[[SPC-pol]] | ||

==References== | ==References== | ||

− | + | <references/> | |

[[category: water]] | [[category: water]] | ||

[[category: models]] | [[category: models]] |

## Latest revision as of 15:20, 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 |

Å | |

kJ mol^{-1}
| |

Å | |

(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]

- ↑ 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
- ↑ 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)