SPC model of water: Difference between revisions

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m (Changed \AA for Å)
(need a negative sign for charge neutrality (or an absolute value))
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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) p. 331 ISBN 902771326X</ref>
UNIQb1b2d8277abe3830-ref-00000015-QINU
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
|-   
|-   
| <math>\sigma</math> || <math> 3.166</math>&#8491;
| UNIQb1b2d8277abe3830-math-00000016-QINU || UNIQb1b2d8277abe3830-math-00000017-QINU&#8491;
|-
|-
| <math>\epsilon</math> || <math>0.650</math> kJ mol<sup>-1</sup>
| UNIQb1b2d8277abe3830-math-00000018-QINU || UNIQb1b2d8277abe3830-math-00000019-QINU kJ mol<sup>-1</sup>
|-
|-
| <math>r_\mathrm{OH}</math> || <math>1.000</math>&#8491;
| UNIQb1b2d8277abe3830-math-0000001A-QINU || UNIQb1b2d8277abe3830-math-0000001B-QINU&#8491;
|-
|-
| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math>
| UNIQb1b2d8277abe3830-math-0000001C-QINU || UNIQb1b2d8277abe3830-math-0000001D-QINU
|-
|-
| <math>q_{\mathrm{O}}</math> ||  <math>-0.82 e</math>
| UNIQb1b2d8277abe3830-math-0000001E-QINU ||  UNIQb1b2d8277abe3830-math-0000001F-QINU
|-
|-
| <math>q_{\mathrm{H}}</math> ||  <math>q_{\mathrm{O}}/2</math> (charge neutrality)
| UNIQb1b2d8277abe3830-math-00000020-QINU ||  UNIQb1b2d8277abe3830-math-00000021-QINU (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.
<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>
UNIQb1b2d8277abe3830-ref-00000022-QINU
==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:
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*[[SPC-pol]]
*[[SPC-pol]]
==References==
==References==
<references/>
UNIQb1b2d8277abe3830-references-00000023-QINU
[[category: water]]
[[category: water]]
[[category: models]]
[[category: models]]

Revision as of 18:01, 24 December 2014

The simple point charge (SPC) model ?UNIQb1b2d8277abe3830-ref-00000015-QINU? 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
?UNIQb1b2d8277abe3830-math-00000016-QINU? ?UNIQb1b2d8277abe3830-math-00000017-QINU?Å
?UNIQb1b2d8277abe3830-math-00000018-QINU? ?UNIQb1b2d8277abe3830-math-00000019-QINU? kJ mol-1
?UNIQb1b2d8277abe3830-math-0000001A-QINU? ?UNIQb1b2d8277abe3830-math-0000001B-QINU?Å
?UNIQb1b2d8277abe3830-math-0000001C-QINU? ?UNIQb1b2d8277abe3830-math-0000001D-QINU?
?UNIQb1b2d8277abe3830-math-0000001E-QINU? ?UNIQb1b2d8277abe3830-math-0000001F-QINU?
?UNIQb1b2d8277abe3830-math-00000020-QINU? ?UNIQb1b2d8277abe3830-math-00000021-QINU? (charge neutrality)

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. ?UNIQb1b2d8277abe3830-ref-00000022-QINU?

Related models

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

References

?UNIQb1b2d8277abe3830-references-00000023-QINU?

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