Difference between revisions of "SPC/E model of water"

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m (Started a Thermal conductivity section)
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{{Stub-water}}
 
{{Stub-water}}
The '''SPC/E''' (extended simple point charge model) <ref>[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)]</ref>
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The '''SPC/E''' (extended simple point charge model) UNIQ11bf423f66a234ea-ref-0000002B-QINU
<ref>[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)]</ref> is a slight reparameterisation  of the [[SPC]] model of [[water]], with a modified value for <math>q_{\mathrm{O}}</math>.
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UNIQ11bf423f66a234ea-ref-0000002C-QINU is a slight reparameterisation  of the [[SPC]] model of [[water]], with a modified value for UNIQ11bf423f66a234ea-math-0000002D-QINU.
 
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:
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| parameter || value
 
| parameter || value
 
|-   
 
|-   
| <math>\sigma</math> || <math> 3.166 </math> &Aring;  
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| UNIQ11bf423f66a234ea-math-0000002E-QINU || UNIQ11bf423f66a234ea-math-0000002F-QINU &Aring;  
 
|-
 
|-
| <math>\epsilon</math> || <math>0.650</math> kJ mol<sup>-1</sup>
+
| UNIQ11bf423f66a234ea-math-00000030-QINU || UNIQ11bf423f66a234ea-math-00000031-QINU kJ mol<sup>-1</sup>
 
|-
 
|-
| <math>r_\mathrm{OH}</math> || <math>1.000</math> &Aring;
+
| UNIQ11bf423f66a234ea-math-00000032-QINU || UNIQ11bf423f66a234ea-math-00000033-QINU &Aring;
 
|-
 
|-
| <math>\angle_\mathrm{HOH}</math> || <math>109.47^{\circ}</math>
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| UNIQ11bf423f66a234ea-math-00000034-QINU || UNIQ11bf423f66a234ea-math-00000035-QINU
 
|-
 
|-
| <math>q_{\mathrm{O}}</math> ||  <math>-0.8476 e</math>
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| UNIQ11bf423f66a234ea-math-00000036-QINU ||  UNIQ11bf423f66a234ea-math-00000037-QINU
 
|-
 
|-
| <math>q_{\mathrm{H}}</math> ||  <math>q_{\mathrm{O}}/2</math> (charge neutrality)
+
| UNIQ11bf423f66a234ea-math-00000038-QINU ||  UNIQ11bf423f66a234ea-math-00000039-QINU (charge neutrality)
 
|}
 
|}
 
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).
 
==Surface tension==
 
==Surface tension==
 
The [[surface tension]] has been studied for the SPC/E model by Vega and Miguel
 
The [[surface tension]] has been studied for the SPC/E 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>
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UNIQ11bf423f66a234ea-ref-0000003A-QINU
 
==Phase diagram==
 
==Phase diagram==
 
[[Image:SPC_E_phase_diagram.png|right|400px]]
 
[[Image:SPC_E_phase_diagram.png|right|400px]]
 
===Plastic crystal phases===
 
===Plastic crystal phases===
 
Recent simulations have demonstrated the existence of  [[Plastic crystals | plastic crystal]] phases for the SPC/E model.
 
Recent simulations have demonstrated the existence of  [[Plastic crystals | plastic crystal]] phases for the SPC/E model.
<ref>[http://dx.doi.org/10.1063/1.3156856  J. L. Aragones and C. Vega "Plastic crystal phases of simple water models", Journal of Chemical Physics '''130''' 244504 (2009)]</ref>
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UNIQ11bf423f66a234ea-ref-0000003B-QINU
 
==Shear viscosity==
 
==Shear viscosity==
The [[shear viscosity]] for the SPC/E model is 0.729 mPa.s at 298 K and 1 bar <ref>[http://dx.doi.org/10.1063/1.3330544 Miguel Angel González and José L. F. Abascal "The shear viscosity of rigid water models", Journal of Chemical Physics '''132''' 096101 (2010)]</ref> (experimental value 0.896  mPa.s <ref>[http://dx.doi.org/10.1021/je049918m Kenneth R. Harris and Lawrence A. Woolf "Temperature and Volume Dependence of the Viscosity of Water and Heavy Water at Low Temperatures", Journal of Chemical & Engineering Data '''49''' pp. 1064-1069 (2004)]</ref>).
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The [[shear viscosity]] for the SPC/E model is 0.729 mPa.s at 298 K and 1 bar UNIQ11bf423f66a234ea-ref-0000003C-QINU (experimental value 0.896  mPa.s UNIQ11bf423f66a234ea-ref-0000003D-QINU).
  
 
==Thermal conductivity==
 
==Thermal conductivity==
[[Thermal conductivity]] <ref>[http://dx.doi.org/10.1063/1.4739855  Frank Römer, Anders Lervik, and Fernando Bresme "Nonequilibrium molecular dynamics simulations of the thermal conductivity of water: A systematic investigation of the SPC/E and TIP4P/2005 models", Journal of Chemical Physics '''137''' 074503 (2012)]</ref>.
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[[Thermal conductivity]] UNIQ11bf423f66a234ea-ref-0000003E-QINU.
  
 
==References==
 
==References==
<references/>
+
UNIQ11bf423f66a234ea-references-0000003F-QINU
 
;Related reading
 
;Related reading
 
*[http://dx.doi.org/10.1063/1.3548869  Péter T. Kiss and András Baranyai "Sources of the deficiencies in the popular SPC/E and TIP3P models of water", Journal of Chemical Physics '''134''' 054106 (2011)]
 
*[http://dx.doi.org/10.1063/1.3548869  Péter T. Kiss and András Baranyai "Sources of the deficiencies in the popular SPC/E and TIP3P models of water", Journal of Chemical Physics '''134''' 054106 (2011)]
 
[[category: water]]
 
[[category: water]]
 
[[category: models]]
 
[[category: models]]

Revision as of 17:04, 24 December 2014

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The SPC/E (extended simple point charge model) ?UNIQ11bf423f66a234ea-ref-0000002B-QINU? ?UNIQ11bf423f66a234ea-ref-0000002C-QINU? is a slight reparameterisation of the SPC model of water, with a modified value for ?UNIQ11bf423f66a234ea-math-0000002D-QINU?. 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 sites, situated on the oxygen atoms. The parameters are as follows:

Thee site water model.png
parameter value
 ?UNIQ11bf423f66a234ea-math-0000002E-QINU?  ?UNIQ11bf423f66a234ea-math-0000002F-QINU? Å
 ?UNIQ11bf423f66a234ea-math-00000030-QINU?  ?UNIQ11bf423f66a234ea-math-00000031-QINU? kJ mol-1
 ?UNIQ11bf423f66a234ea-math-00000032-QINU?  ?UNIQ11bf423f66a234ea-math-00000033-QINU? Å
 ?UNIQ11bf423f66a234ea-math-00000034-QINU?  ?UNIQ11bf423f66a234ea-math-00000035-QINU?
 ?UNIQ11bf423f66a234ea-math-00000036-QINU?  ?UNIQ11bf423f66a234ea-math-00000037-QINU?
 ?UNIQ11bf423f66a234ea-math-00000038-QINU?  ?UNIQ11bf423f66a234ea-math-00000039-QINU? (charge neutrality)

The SPC/E model has a dipole moment of 2.351 D. (Ref. 1 Table I).

Surface tension

The surface tension has been studied for the SPC/E model by Vega and Miguel ?UNIQ11bf423f66a234ea-ref-0000003A-QINU?

Phase diagram

SPC E phase diagram.png

Plastic crystal phases

Recent simulations have demonstrated the existence of plastic crystal phases for the SPC/E model. ?UNIQ11bf423f66a234ea-ref-0000003B-QINU?

Shear viscosity

The shear viscosity for the SPC/E model is 0.729 mPa.s at 298 K and 1 bar ?UNIQ11bf423f66a234ea-ref-0000003C-QINU? (experimental value 0.896 mPa.s ?UNIQ11bf423f66a234ea-ref-0000003D-QINU?).

Thermal conductivity

Thermal conductivity ?UNIQ11bf423f66a234ea-ref-0000003E-QINU?.

References

?UNIQ11bf423f66a234ea-references-0000003F-QINU?

Related reading