Theoretical study of the n-body interaction energies of the ring, cage and prism forms of (H2O)6

The MP2 method is used together with basis sets as large as aug-cc-pVQZ to calculate the binding energies and the various n-body interaction energies of the ring, cage and prism forms of (H2O)6. It is found that nearly all of the energy changes due to adoption of basis sets more flexible than aug-cc-pVDZ and to the inclusion of electron correlation effects are due to the 2-body interactions.