SPC/E model of water

The SPC/E (extended simple point charge model) is a slight reparameterisation of the SPC model of water, with a modified value for $q_{\mathrm {O} }$. 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:

parameter	value
$\sigma$	$3.166{\mathrm {\AA} }$
$\epsilon$	$0.650$ kJ mol-1
$r_{\mathrm {OH} }$	$1.000\mathrm {\AA}$
$\angle _{\mathrm {HOH} }$	$109.47^{\circ }$
$q_{\mathrm {O} }$	$-0.8476e$
$q_{\mathrm {H} }$	$q_{\mathrm {O} }/2$ (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

Phase diagram

Plastic crystal phases

Recent simulations have demonstrated the existence of plastic crystal phases for the SPC/E model.

Shear viscosity

The shear viscosity for the SPC/E model is 0.729 mPa.s at 298 K and 1 bar (experimental value 0.896 mPa.s ).

References

Related reading

• 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)