TABLE 8.

Summary of Electrostatic Properties for the Amide Series^a,^b

	|μ| (Debye)		TR($\stackrel{‒}{\alpha }$)(Å3)		〈|μ|〉 (Debye)			ε
molecule	QM	Drude	QM	Drude	CP	Drude	GK, Drude	expt1	Drude
acetamide	4.0	4.0	5.9	6.1	6.0	5.8	2.4 ± 0.2	66.3	66 ± 3
NMA	3.9	3.9	7.8	7.9	*5.9	5.7	4.6 ± 0.6	100	92 ± 5
N,N-dimethyl acetamide	4.0	3.9	9.6	9.5	5.2	5.0	1.7 ± 0.1	26	23 ± 1

^aProperties of the Drude polarizable model are compared with QM and experimental data. The Drude model corresponds to the optimal choice of LJ parameters from the unscaled/vthole class of electrostatic models. Included is the gas-phase dipole (|μ|) and trace of the molecular polarizability ($\stackrel{‒}{\alpha }$). Also included is the average molecular dipole 〈|μ|〉 and Kirkwood G_K factor calculated from neat liquid simulations at 373 K and the corresponding dielectric constant calculated from eq 7. The NMA CP simulation was run at T = 308 K where 〈|μ|〉 = 6.0 Debye.⁸⁶ We estimate a drop in of ≈0.1 Debye for a simulation run at T = 373 K on the basis of the behavior of the Drude polarizable model.