SPC model of water

The simple point charge (SPC) model 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
\(\sigma\)	\( 3.166 {\mathrm {\AA}}\)
\(\epsilon\)	\(0.650\) kJ mol-1
\(r_\mathrm{OH}\)	\(1.000\mathrm{\AA}\)
\(\angle_\mathrm{HOH}\)	\(109.47^{\circ}\)
\(q_{\mathrm{O}}\)	\(-0.82 e\)
\(q_{\mathrm{H}}\)	\(q_{\mathrm{O}}/2\) (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.

Related models

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

• SPC
• SPC/E
• SPC/F
• SPC/F2
• SPC/FP
• SPC/FQ
• SPC/Fw
• SPC/HW
• SPCP
• SPC-pol