H. Eugene Stanley is funded by a grant from the Theoretical and Computational Chemistry Program to study cooperative molecular motions in water. The aim of the research is to conduct systematic studies of the effects of the cooperative molecular motions on the properties of water in an effort to understand: 1) power law singularities observed in the thermodynamic response functions and relaxation times; 2) the shape of phase boundaries in the phase diagram of water; and 3) anomalies found in the propagation of sound through water. A combination of molecular dynamics simulations and formal theoretical modeling will be used to develop a dynamical model of liquid water. Molecular dynamics calculations will use fast multipole methods on systems containing up to a million water molecules using the Origin 2000 at Boston University. The calculations will be performed with a parallelized code developed in Stanley's research group. Observable properties such as diffusivity, spin lattice relaxation, dielectric function and dynamic structure factors will be determined from the simulations for comparison with experiment. Stanley will collaborate with three experienced experimentalists who will provide data to characterize a hypothesized second critical point for water. Water is an important fluid. Although this substance has been the topic of considerable research since the beginning of the century, its peculiar properties are still not completely understood. Although agreement has not been reached on the origin of the anomalous properties of water, it is commonly believed that a central role is played by the possibility for the water molecule to form hydrogen bonds and to create a tetrahedrally coordinated open network in both the solid and the liquid phases. Stanley's research is directed at a fundamental molecular level explanation for the anomalous behavior of this ubiquitous fluid
