TABLE I.

CPU times of 80 ps QM/MM MD simulations using various QM/MM electrostatic treatments (time in hours).

${\mathrm{NH}}_4^{+}\dots {\mathrm{Cl}}^{-}$
Rc (Å)	Ewalda	Cutoff	IPS	DSF
12	17.84	3.55	5.46	6.89
14	20.22	5.49	8.78	11.23
ClCH3…Cl−
Rc (Å)	Ewalda	Cutoff	IPS	DSF
12	18.80	3.80	5.71	7.18
14	21.38	5.86	9.18	11.69

^aParticle-mesh Ewald (PME) is used for treating MM/MM electrostatic interactions in the QM/MM-Ewald simulations.