Development of transferable interaction models for water. II. Accurate energetics of the first few water clusters from first principles

An overview is given on estimates of the MP2 complete basis set limits for the ring minima of water trimer to pentamer and several water hexamer isomers. The largest calculations reported require the current state-of-the-art in both electronic software and hardware. In the absence of experimental data for the energetics of small clusters these results, when coupled with accurate estimates for the zero-point energy corrections, can serve as benchmarks in evaluating the accuracy of interaction potentials for water as well as guiding future experimental studies aiming at probing the energetics of small water clusters.