Table 4:

Performance of recalibrated NMA and acetate models in yielding target binding energies. Target binding energies are taken from a benchmarked vdW-inclusive DFT method. Target energies are divided into two categories. Low field target energies include NMA-NMA, NMA-water and acetate-water dimerization energies as well as binding energies of one acetate with two waters. High field target energies include binding energies of ions with 1–4 NMA and 1–2 acetate molecules. RMSE are estimated with respect to target energies. All energies are in kcal/mol.

	Target	Orig.	Set1	Set2	Set3	Set4	Set5
Low field
NMA-NMA dimer	−9.2	−8.6	−7.3	−8.1	−8.1	−8.8	−7.4
Water-NMA dimerl	−5.4	−5.2	−4.5	−4.4	−5.9	−5.9	−4.9
Water-NMA dimer2	−8.3	−8.2	−7.3	−7.4	−6.8	−6.9	−7.3
RMSE		0.4	1.3	1.0	1.1	0.9	1.2
Acetate-water	−19.7	−17.6	−19.0	−19.0	−19.0	−19.1	−19.0
Acetate-(water)2	−36.5	−33.9	−36.5	−36.5	−36.5	36.5	−36.5
RMSE		2.4	0.5	0.5	0.5	0.4	0.5
High field
Na+(NMA)1	−41.8	−37.3	−42.7	−42.6	−42.9	−42.4	−41.5
Na+(NMA)2	−75.3	−68.3	−75.6	−75.2	−75.4	−74.8	−73.9
Na+(NMA)3	−99.2	−93.1	−100.5	−99.9	−98.8	−99.1	−98.8
Na+(NMA)4	−117.2	−113.2	−120.3	−118.5	−117.3	−117.3	−118.0
RMSE		5.5	1.8	0.8	0.6	0.4	0.8
K+(NMA)1	−32.6	−28.3	−30.4	−31.5	−32.6	−32.4	−32.2
k+(nma)2	−58.0	−52.3	−54.8	−56.0	−57.5	−57.3	−57.6
k+(nma)3	−78.4	−71.9	−74.7	−76.1	−76.8	−77.3	−78.0
k+(nma)4	−93.8	−90.8	−93.4	−94.9	−95.2	−95.5	−96.9
RMSE		5.0	2.7	1.7	1.1	1.1	1.6
Na+(acetate) 1	−148.3	−144.7	−149.3	−149.0	−149.3	−149.8	−149.5
Na+(acetate)2	−198.7	−193.3	−198.9	−198.9	−199.0	−199.5	−199.2
RMSE		4.6	0.7	0.5	0.8	1.1	0.9
K+(acetate)1	−130.7	−130.3	−130.2	−130.1	−130.5	−130.4	−129.8
K+(acetate)2	−174.8	−173.7	−175.3	−175.3	−175.5	−175.5	−175.0
RMSE		0.8	0.5	0.5	0.5	0.5	0.7