Editing SPC/E model of water
Jump to navigation
Jump to search
The edit can be undone. Please check the comparison below to verify that this is what you want to do, and then publish the changes below to finish undoing the edit.
Latest revision | Your text | ||
Line 1: | Line 1: | ||
{{Stub-water}} | {{Stub-water}} | ||
The | The extended simple point charge model, '''SPC/E''' is a slight reparameterisation of the [[SPC]] model of [[water]], with a modified value for <math>q_{\mathrm{O}}</math>. | ||
The molecule is modelled as | 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. 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: | [[Image:Water_empirical1.png|center|300px]] | ||
{| 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> | ||
Line 19: | Line 18: | ||
| <math>q_{\mathrm{O}}</math> || <math>-0.8476 e</math> | | <math>q_{\mathrm{O}}</math> || <math>-0.8476 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/E model has a [[dipole moment]] of 2.351 D. (Ref. 1 Table I) | The SPC/E model has a [[dipole moment]] of 2.351 D. (Ref. 1 Table I), | ||
==References== | ==References== | ||
#[http://dx.doi.org/10.1021/j100308a038 H. J. C. Berendsen, J. R. Grigera, and T. P. Straatsma "The missing term in effective pair potentials", Journal of Physical Chemistry '''91''' pp. 6269 - 6271 (1987)] | |||
#[http://dx.doi.org/10.1063/1.2841127 Swaroop Chatterjee, Pablo G. Debenedetti, Frank H. Stillinger, and Ruth M. Lynden-Bell "A computational investigation of thermodynamics, structure, dynamics and solvation behavior in modified water models", Journal of Chemical Physics '''128''' 124511 (2008)] | |||
[[category: water]] | [[category: water]] | ||
[[category: models]] | [[category: models]] |