Table 3.

Water cluster binding energies (kcal/mol) with HIPPO compared to ab initio calculations.

Cluster	Structure	Reference	HIPPO	HIPPO Minimum	Difference
Trimera		−15.77	−15.417	−15.767	0.00
Tetramera		−27.39	−25.695	−26.685	0.71
Pentamera		−35.90	−32.994	−34.582	1.32
Hexamerb	Prism	−45.92	−44.169	−46.145	−0.23
	Cage	−45.67	−43.635	−45.387	0.28
	Bag	−44.30	−41.106	−43.364	0.94
	Chair	−44.12	−40.484	−42.543	1.58
	Book A	−45.20	−42.359	−44.245	0.96
	Book B	−44.90	−42.103	−43.958	0.94
	Boat A	−43.13	−39.576	−41.548	1.58
	Boat B	−43.07	−39.612	−41.555	1.52
Octamera	D2d	−73.0	−68.309	−71.547	1.5
	S4	−72.9	−68.253	−71.559	1.3
11-mera	43’4	−104.6	−94.775	−100.232	4.4
	515a	−1040	−93.635	−99.377	4.6
16-mera	AABB	164.1	−155.457	−161.556	2.5
	ABAB	164.2	−155.875	−161.836	2.4
	Antiboat	164.6	−152.799	−159.634	5.0
	Boat A	164.4	−152.457	−159.357	5.0
	Boat B	164.2	−152.400	−159.425	4.8
17-mera	552’5	−175.7	−161.740	−169.938	5.8
	Sphere	−175.0	−162.549	−170.681	4.3
				MAD:
Summary:	Dimer – Hexamer			0.57
	Octamer – 17-mer			3.8

^aStructures and reference values from reference 73.

^bHexamer structures and reference energies from reference 74.