George C. Pimentel Seminar in Physical Chemistry: The Dynamics of Protons in Liquid Water Viewed through Ultrafast IR Spectroscopy

Seminar | October 3 | 4-5 p.m. | 120 Latimer Hall

 Prof. Andrei Tokmakoff, Department of Chemistry, University of Chicago

 College of Chemistry

Studying the structure of the excess proton in liquid water and the manner in which the excess charge is transported through water’s dynamic hydrogen bond network remains a daunting experimental challenge. This process has long been attributed proton transfer involving a sequential displacement of protons along a chain of hydrogen bonds that displaces the excess charge over long distance but not a particular proton. Although the excess charge is commonly described as hydronium, there is little experimental evidence to describe the structure of the aqueous proton complex or the mechanism of transport. I will describe investigations of the infrared continuum band observed in strong acid solutions using time-resolved IR spectroscopy to gain insight into these problems. Two-dimensional infrared spectroscopy is used to track the time-dependent vibrational frequencies of the aqueous proton complex as it evolves. These results are interpreted with the assistance of spectral modeling based on molecular dynamics simulations.

 Light refreshments will be served at 3:50 at The Coffee Lab, 510-643-0572

 Reception to follow in Bixby Commons