Direct probing of low frequency motions in solution phase chemical dynamics

In this project funded by the Experimental Physical Chemistry Program of the Chemistry Division, David Blank will develop and apply novel experimental methods designed to address the role of intermolecular and low frequency intramolecular nuclear motions in condensed-phase reactive and nonreactive chemical dynamics. The experiments utilize multidimensional femtosecond spectroscopic techniques, and can be divided into two types, based on the complementary information each will provide. First, the response of low frequency motions in response to the progress of a dynamic event in solution will be probed by photo-initiating that event with an ultrafast laser pulse, and monitoring the response using third-order time domain Raman spectroscopy. Second, the coupling between low frequency motions in condensed systems will be directly measured using a new resonance enhanced version of coherent two-dimensional time domain Raman spectroscopy. These studies are expected to enable new insights into low frequency motions in solution phase chemical reactions.

The significant proportion of chemistry, from industrial reactions to the chemistry of biology, takes place in the solution phase. This project aims at providing a microscopic description of chemical reactivity in solution, one of the central issues in physical chemistry today. The proposed methods are direct and generally applicable techniques that will aid in understanding the scientific issues involved. This work has applications ranging from modern optics and metrology to advanced materials characterization and fundamental research in condensed matter. As part of this research effort, students from the undergraduate through the postdoctoral level are trained with state-of-the-art instrumentation in ultrafast laser technology, an emerging field in the physical sciences.