Table 1.

Non-bonded Lennard-Jones (LJ) and Coulombic (Coul) contributions to the computed binding enthalpies (ΔH; in kcal/mol), at a variety of NaCl concentrations (in mM). The bonded contributions, not listed, make up the differences. The experimental binding enthalpy is −15.8 kcal/mol at 0 mM NaCl⁵⁰. The SEM values are less than 0.2 kcal/mol for all computed terms. The TIP3P, SPC/E and TIP4P-Ew models were used with their corresponding Na⁺ and Cl⁻ parameters from Joung and Cheatham³⁴, and OPC was used with the parameters tuned for TIP4P-Ew.

NaCl conc	TIP3P			SPC/E			TIP4P-Ew			OPC
	LJ	Coul	ΔH	LJ	Coul	ΔH	LJ	Coul	ΔH	LJ	Coul	ΔH
0	−13.3	−7.0	−21.6	−10.5	−10.8	−22.2	−9.1	−12.8	−23.4	−7.7	−9.6	−18.9
100	−12.7	−5.9	−19.7	−10.1	−4.0	−15.0	−9.6	−4.0	−14.7	−10.0	0.6	−10.9
300	−12.8	−4.7	−18.7	−10.1	−3.5	−14.8	−10.0	−2.1	−13.5	−10.2	1.2	−10.4
500	−12.7	−4.6	−18.2	−10.0	−2.8	−13.9	−10.0	−1.2	−13.1	−10.7	2.2	−10.0