C. R. Baiz, K. J. Kubarych, J. Am. Chem. Soc. 132 (2010) 12784-12785

We present the first implementation of transient vibrational Stark-effect spectroscopy as an ultrafast probe of solvation dynamics. The method is applied to the phototriggered intramolecular charge-transfer reaction of Betaine-30, where the vibrational Stark shifts of the nearby solvent molecules—arising from the change in the electrostatic environment—are measured using a three-pulse photon echo probe. This new experiment provides a direct sub-picosecond measure of the chromophore’s excited-state dynamics and back-electron transfer as viewed from the solvent’s perspective. We develop a simple ab-initio model that offers semi-quantitative prediction of the experimental Stark shifts.

This work was highlighted in the Science Concentrates section of C&E News and in a University of Michigan press release. This work will also be the subject of an upcoming television production on the Out of the Blue series which airs nationally on the Big Ten Network.