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. 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
$r_{\mathrm {OH} }$	$1.000\mathrm {\AA}$
$\angle _{\mathrm {HOH} }$	$109.47^{\circ }$
$q_{\mathrm {O} }$	$-0.82e$
$q_{\mathrm {H} }$	$q_{\mathrm {O} }/2$ (charge neutrality)

The SPC model has a dipole moment of 2.27 D.

Related models

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

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