Physical Chemistry Seminar: Professor Jahan Dawlaty, University of Southern California

Physical Chemistry Seminar: Professor Jahan Dawlaty, University of Southern California (Host: Dick Zare)

About the Seminar

"Electric Fields and Polarization at Interfaces for Catalysis: A Spectroscopic View"

Sustaining local electric fields in confined microscopic environments as polarizing agents for catalyzing reactions is important. It is argued that many enzymes operate based on this principle and lessons learned from them can be extended to other catalytic systems. We use Stark shift spectroscopy to measure electric fields in electrochemical interfaces for understanding solvation, interfacial polarization, molecular structure, steric hindrance, and frustrated bond formation. We will present experimental results on fields at the junction of electrolytes and biased metal electrodes. Both simple dilute electrolytes that are mostly described by the continuum Gouy-Chapman model and its variants, and ionic liquids which deviate from such a description will be discussed. A major challenge is engineering and designing local environments that can sustain such fields. With inspiration from the relatively new field of Frustrated Lewis Pairs (FLPs), we report our results on Lewis bonds near a surface. We comment on the electric field perspective of the mechanism of FLP catalysis and propose approaches on how to use frustrated Lewis pairs as polarizing environments near an electrode for driving reactions. Results on the connection between a polarizing electric field at an electrochemical interface and the polarizing effect of organic substituents in homogenous catalysis will also be presented.

About the Speaker

Jahan Dawlaty finished his undergraduate degree in chemistry with emphasis on physical chemistry from Concordia College in Minnesota. He joined Cornell University in 2001 for graduate studies, where he worked both in chemistry and electrical engineering departments. For postdoctoral work, he joined UC Berkeley Chemistry Department, where he worked on ultrafast spectroscopy of exciton transfer in photosynthetic complexes. He started his independent career in 2012 at the University of Southern California, where he is an associate professor of chemistry. His research areas are spectroscopy of interfaces with particular attention to local electric fields, and ultrafast dynamics of proton transfer in molecular systems.