Professor Robert Baker
Physical Chemistry Seminar
Department of Chemistry and Biochemistry
The Ohio State University
Description
Title: Observing Ultrafast Electron Motion in Catalytic Systems: New Ways to Visualize Charge and Spin Dynamics at Interfaces
Abstract: Understanding and controlling electron dynamics at interfaces is at the heart of numerous applications ranging from heterogenous catalysis to information processing. To directly observe these dynamics, we have developed ultrafast XUV reflection spectroscopy as a surface sensitive analog of time-resolved x-ray absorption. In these measurements, high harmonic generation of attosecond to femtosecond XUV pulses enables real-time observation of charge and spin dynamics with element specificity, ultrafast time resolution, and near atomic layer surface sensitivity. This talk will highlight recent studies of surface electron dynamics in materials ranging from photocatalysts to magnetic semiconductors to systems displaying chiral-induced spin selectivity (CISS). In addition to ultrafast electron transfer, we also study the interfacial solvation structure in electrocatalytic systems using in-situ sum frequency generation vibrational spectroscopy. This complimentary tool enables direct measurement of solvent-mediated electric fields at catalytic interfaces, which are found to significantly influence the kinetics of electrochemical CO2 activation and reduction. Last, I will briefly describe the National eXtreme Ultrafast Science (NeXUS) facility. This $10M infrastructure project provides attosecond and femtosecond pulses of XUV light with tailored bandwidth to a suite of experimental end-stations enabling molecular and material characterization with unprecedented temporal and spatial resolution. This facility, which is supported by the National Science Foundation, will soon become an international open-access user facility serving the entire chemical, physics, and materials communities.
