This grant in the Theoretical and Computational Program of the Chemistry Division is aimed at improving our molecular-level understanding of the structure and dynamics of solutions. Such advances can help one predict how chemical reactions in solution are affected by the ion-ion and ion-solvent forces. Recently the electron exchange between ferrous and ferric ions, a paradigm of oxidation-reduction reactions in solution, was investigated with respect to the effect of changing the solvent from water to heavy water. The results invite further model studies of the structure and dynamics of the ion-water hydration complex. Another aspect concerns effects of fluctuating polarization fields in the medium. A new theory gives a unified view of the thermodynamic and dynamic aspects for the usual dielectric models; it invites being extended to molecular models. The ion distributions in solution provide a connection between the effects of ions on chemical reactions and other solution properties including activity coefficients, electrical conductance, NMR relaxation, and diffraction of x-rays and neutrons. Current research includes the development of the theory of transport in solutions so that conductivity in the molar concentration range and even in mixed electrolytes can be related to the ion distributions and the models from which they are calculated.
