Editing SPC model of water
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The '''simple point charge''' (SPC) model | {{Stub-water}} | ||
The '''simple point charge''' (SPC) model is an [[Empirical 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. 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: | ||
a rigid isosceles triangle, having charges situated on each of the three atoms. | [[Image:Water_empirical1.png|center|300px]] | ||
[[Image: | |||
{| border="1" | {| border="1" | ||
|- | |- | ||
| 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) | ||
|- | |||
| <math>r_\mathrm{OM}</math> || <math>0</math> (charge sits on oxygen) | |||
|} | |} | ||
The SPC model has a [[dipole moment]] of 2.27 D. | The SPC model has a [[dipole moment]] of 2.27 D. | ||
==References== | ==References== | ||
#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). | |||
[[category: water]] | [[category: water]] | ||
[[category: models]] | [[category: models]] |