Theoretical Studies of Solvation and Reaction Dynamics in Polar and Nonpolar Solvents

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Hyung Kim of Carnegie-Mellon University is supported by the Theoretical and Computational Chemistry Program to carry out theoretical studies of solvation and chemical reactions and related electronic spectroscopy in diversified solution environments, such as dipolar and non-dipolar solvents. By incorporating spatial dispersion into reaction field theory with the aid of molecular dynamics (MD) simulations, Kim will construct an accurate continuum theory to describe equilibrium and nonequilibrium solvation in polarizable, non-dipolar, quadrupolar solvents, such as benzene. Quantum chemistry techniques will be applied to solvation of small molecules and various charge-shift processes, such as Menshutkin and excited-state electron transfer reactions in benzene and other quadrupolar solvents. With the combined efforts of MD, quantum chemistry, and continuum theory, this effort will provide the first systematic study of charge-shift reactions in quadrupolar solvents with proper account of nonequilibrium solvation and associated solute-solvent electronic structure variations. In parallel with this effort, the truncated adiabatic basis-set (TAB) solvent electronic description will be improved to study the condensed-phase properties of water. Specifically, the TAB formulation will be extended to incorporate the pairwise-non additive, many-body character of both van der Waals and Coulombic interactions into the simulations. This is expected to allow the short- and long-range interactions to fluctuate with the solvent configurations and vary with the thermodynamic conditions. This method will be applied to study liquid-vapor phase equilibria, solvation dynamics, linear/nonlinear electronic spectroscopy, and ion transport in water under ambient and supercritical conditions. Many chemical reactions occur in condensed phases consisting of reacting solutes that are dissolved in nonreacting liquid solvents. Water, for example, is a solvent of vital interest to chemistry, biochemistry, and chemical engineering. Supercritical water is technologically important, and this research helps provide useful theoretical models that can have long-range impacts on the fundamental understanding of industrially significant solvation effects.