Interaction potentials for water from accurate cluster calculations

Recent advances in the area of ab initio theory combined with the development of efficient electronic structure software suites that take advantage of parallel hardware architectures, have resulted in our ability to obtain accurate energetics for medium-size (up to 30 molecules) clusters of water molecules. These advances offer a new route in the development of empirical interaction potentials for water, especially in the absence of experimental information regarding the cluster energetics. The use of systematically improvable methodological approaches, together with the understanding of the salient issues associated with the transferability of the models across different environments, allow for the development of hierarchical approaches in the description of the intermolecular interactions in water. The use of accurate models, which are transferable across dissimilar environments, in conjunction with quantum dynamical simulation protocols, can provide new insight into the origin of the anomalous behavior of water across the various temperature and pressure ranges that are pertinent to its chemical and biological.