Table 3.

LEWIS predictions for energies of small neutral clusters

Molecule	Number	nh	–ΔE (kJ/mol)	–ΔEbond (kJ/mol)	rOO (Å)
(H2O)4	4	4	142.1	35.53	2.71–2.72
(H2O)5	5	5	191.4	38.28	2.62–2.71
(H2O)6(cyclic)	6	6	241.2	40.20	2.66–2.67
(H2O)6(twistedprism)	6	7	243.0	34.72	2.63–2.87
(H2O)8(D2d)	8	12	374.9	31.24	2.71–2.88
(H2O)8(S4)	8	12	374.9	31.24	2.71–2.90

n_h = number of hydrogen bonds

The association enthalpy is given by ΔE = E_cluster - nE_H2O, and the energy per hydrogen bond is given by ΔE_bond = ΔE/n_h. For O–O distances (r_OO), ranges are given