Theoretical and Computational Studies of Chemical Reaction Dynamics

Many chemical reactions that are essential to biological function (e.g. electron transfer, proton transfer, isomerization, and recognition/binding processes) occur in aqueous environments whose structural and dynamical properties differ greatly from bulk solution. Understanding electron and proton transfer chemistry is also essential to the design and function of new materials and devices such as solar photocells, hydrogen fuel cells, and semiconductor photocatalysts. Obtaining a detailed molecular-level picture of how complex environments influence the dynamics of chemical reactions represents a fundamental challenge to chemistry.

The Corcelli group is active in the development of new theoretical approaches and computational tools for studying chemical reactions in complex environments. The molecules directly involved in the reaction are typically treated with quantum chemical techniques, while the surrounding environment is simulated with classical molecular dynamics. This combination of methods offers tremendous flexibility in making a direct connection to experimental studies. For example, the recent development of femtosecond infrared laser pulses provides the opportunity to study dynamical processes in chemistry, biology, and materials science with exceptional time resolution and sensitivity to molecular detail. Infrared spectroscopy is a powerful tool because the frequency of a vibrational probe, for example an isotopically labeled CD₃ group in a protein or the OH vibrations of a water molecule, is remarkably sensitive to its surroundings. As a chemical reaction proceeds in time, a nearby vibrational probe experiences a change in its environment, and this change can be monitored in real-time with femtosecond infrared spectroscopy. The theoretical methods being developed in the Corcelli group can be used for the computation of spectroscopic signals (infrared, UV-Vis, etc…) as simulated reactions proceed. These calculations complement spectroscopic studies to provide a detailed understanding of the reaction of interest.