SWM4-DP model of water

The SWM4-DP model of water has a TIP4P like structure, as well as incorporating a Drude oscillator.

Parameters

$r_{\mathrm {OH} }$ (Å)	$\angle$HOH (deg)	$\sigma$ (Å)	$\epsilon$ (kcal/mol)	q(O) (e)	q(H) (e)	q(M) (e)	$r_{\mathrm {OM} }$ (Å)	q(Drude) (e)	k(Drude) (kcal/mol/Å2)
0.9572	104.52	3.1803	0.20568	-1.77185	0.5537	-2q(H)	0.23808	-q(O)	1000

SWM4-NDP

The SWM4-NDP model is a version that has been re-optimized for negatively charged Drude particles. The parameters are given by:

$r_{\mathrm {OH} }$ (Å)	$\angle$HOH (deg)	$\sigma$ (Å)	$\epsilon$ (kcal/mol)	q(O) (e)	q(H) (e)	q(M) (e)	$r_{\mathrm {OM} }$ (Å)	q(Drude) (e)	k(Drude) (kcal/mol/Å2)
0.9572	104.52	3.18395	0.21094	1.71636	0.55733	-2q(H)	0.24034	-q(O)	1000

SWM6

The SWM6 model is a six-site model that adds oxygen lone-pairs ($L$) to the SWM4-NDP model. The parameters are given by:

$r_{\mathrm {OH} }$ (Å)	$\angle$HOH (deg)	$\angle$LOL (deg)	$R_{\mathrm {min,O} }$ (Å)	$\epsilon$ (kcal/mol)	q(O) (e)	q(H) (e)	q(M) (e)	q(L) (e)	$r_{\mathrm {OM} }$ (Å)	Failed to parse (SVG (MathML can be enabled via browser plugin): Invalid response ("Math extension cannot connect to Restbase.") from server "https://wikimedia.org/api/rest_v1/":): {\displaystyle r_{\mathrm {OL}}} (Å)	q(Drude) (e)	k(Drude) (kcal/mol/Å2)
0.9572	104.52	101.098	3.59	0.162	1.91589	0.53070	-1.1334	-0.108	0.247	0.315	-1.62789	1000