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. Author manuscript; available in PMC: 2013 Jan 31.
Published in final edited form as: J Chem Theory Comput. 2011 Apr 12;7(4):857–867. doi: 10.1021/ct100638g

Table 7.

Interaction energies (kcal/mol) of water clusters from single-point calculations using the fixed geometries from Reference 50a

Structure PMO AM1 MNDO PM3 RM1 PM6 PM3-D PDDG-
PM3		 reference
(H2O)2 −4.6 −2.9 7.1 −2.5 −0.9 −3.8 −4.3 −0.9 −5.0
(H2O)3 cycle −8.3 −2.3 40.6 −9.2 −1.4 −11.8 −20.9 −7.5 −15.8
(H2O)4 cycle −25.1 −5.8 45.0 −17.8 −6.7 −20.7 −28.5 −17.1 −27.4
(H2O)5 cycle −28.1 2.2 70.2 −18.6 −9.4 −24.5 −40.0 −25.1 −35.9
(H2O)6 cycle −41.3 −4.9 68.6 −27.5 −14.4 −32.8 −44.6 −30.6 −44.3
(H2O)6 cage −42.2 −16.0 78.0 −24.5 −7.0 −33.9 −44.2 −17.8 −46.0
(H2O)6 book −42.2 −10.1 74.8 −26.8 −10.3 −33.5 −45.2 −24.6 −45.8
(H2O)6 prism −42.3 −21.1 76.5 −21.9 −7.4 −34.9 −41.8 −14.4 −45.3
(H2O)8 D2h −69.1 −22.6 121.4 −39.5 −12.4 −53.9 −70.6 −30.3 −72.6
Mean unsigned
deviation		 3. 9 28.3 102.3 16.6 29.8 9.8 2.1 18.9
a

Structures and reference energies from Reference 50. The interaction energy is calculated relative to the infinitely separated gas-phase monomers with geometries frozen in the monomer geometry given in Reference 50.