SPC/HW model of water

The SPC/HW model is an SPC model designed for heavy 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, i.e. (Eq. 1 in ):

$\Phi _{i,j}=\left[{\frac {C_{12}}{r_{OO}(i,j)}}\right]^{12}-\left[{\frac {C_{6}}{r_{OO}(i,j)}}\right]^{6}+\sum _{\alpha =1}^{3}\sum _{\beta =1}^{3}{\frac {q_{\alpha }(i)q_{\beta }(j)}{r_{\alpha \beta }(i,j)}}$

The parameters are as follows (Ref 1 Table I. Note, in the table the HOH (DOD) angle is given as 109.43 but in the text as 109.47):

parameter	value
$C_{12}$	$0.3428$ (kJ mol-1) 1/12nm
$C_{6}$	$0.3712$ (kJ mol-1) 1/6nm
$r_{\mathrm {OH} }$	$1.000$ Å
$\angle _{\mathrm {HOH} }$	$109.47^{\circ }$
$q_{\mathrm {O} }$	$-0.87e$
$q_{\mathrm {H} }$	$q_{\mathrm {O} }/2$ (charge neutrality)

References

Related reading

• Dibyendu Bandyopadhyay, Sadhana Mohan, Swapan K. Ghosh, and Niharendu Choudhury "Properties of Heavy Water in the Temperature Range T = 223 K to 373 K from Molecular Dynamics Simulation Using the Simple Point Charge/Heavy Water (SPC/HW) Model", Journal of Chemical and Engineering Data 57 pp. 1751-1758 (2012)