TABLE 6.

Summary of Drude Polarizable and Charmm NMA Properties^a

properties	experiment	CHARMM	Drude (unscaled/vthole)	Drude (scaled/vthole)
ΔHvap (T = 373 K), kcal/mol	–15.1, –13.8	–13.4 ± 0.01	–15.3 ± 0.01	–14.2 ± 0.01
<v> (T = 373 K), Å3	135.9	133.0 ± 0.05	135.6 ± 0.05	134.6 ± 0.05
ΔGhydr (T = 298 K), kcal/mol	–10.1	–7.8 ± 0.2	–10.9 ± 0.2	–10.0 ± 0.2
ε (T = 373 K)	100.0	37 ± 2	92 ± 5	56 ± 2
τD (T = 308 K)	590, 740	140 ± 20	660 ± 60	260 ± 40
diffusion (T = 373 K), Å2/ps	0.14, 0.12	0.20 ± 0.01	0.13 ± 0.01	0.17 ± 0.01

^aThe Drude model corresponds to the optimal choice of LJ parameters from the unscaled/vthole class of electrostatic models. The TIP3P⁹⁵ and SWM4-NDP²⁰ water models are used to solvate the CHARMM and Drude NMA models, respectively. Models are compared to experimental data.^{10–13,77,78,98–101} The diffusion constant is calculated from a simulation at 373 K from the asymptotic time dependence of the mean-square displacement of the molecules as a function of time, 〈Δr(t)²〉 → 6Dt. The experimental diffusion constants correspond to a linear interpolation of available temperature-dependent data¹⁰¹ to T = 373K and an estimate at T = 373K.¹⁰⁰ The MD results include a correction for finite size effects in periodic boundary conditions, D = D_pbc + 2.837297k_BT/(6πηL).¹⁰² The viscosity at T = 373 K is estimated from available temperature-dependent data, assuming η ∝ 1/T.¹⁰¹