VINSE Colloquium Series: “Transient studies of vibration-cavity polaritons” Dr. Adam Dunkelberger, Naval Research Lab 3/22/23
Dr. Adam Dunkelberger
Research Chemist
U.S. Naval Research Laboratory
03.22.23 | 4:10PM | Stevenson 5326
Light refreshments served at 3:45PM
Abstract: Vibration-cavity polaritons, which are produced by strong coupling between an optical cavity and a molecular vibration, have been shown to modify chemical reaction rates and branching ratios. However, the underlying mechanisms for the observed effects are poorly understood. In order to gain insight into how these polaritons might alter molecular processes, we have used ultrafast pump-probe and two-dimensional infrared (2D IR) spectroscopies to characterize coherent and incoherent polariton excited state behaviors. Our earlier studies on tungsten hexacarbonyl (W(CO)6) strongly coupled to a Fabry-Pérot cavity demonstrated that much of the response is due to so-called reservoir or uncoupled excited state absorption as well as polariton contraction. In recent studies, we have used 2D IR and spectrally filtered pump-probe studies on the nitroprusside anion (Fe(CN)5NO2-) in methanol to determine the transition frequencies and dynamics of polariton excited states allowing us to extract polariton dephasing timescales, which follow those of the cavity and molecule, as well as incoherent polariton population which decays at a significantly longer timescale.
Bio: Adam graduated from The Ohio State University in 2007 with a BS in Chemistry and then went on to complete a PhD in Physical Chemistry at the University of Wisconsin-Madison in 2013. He was a Mirzayan Science and Technology Policy Fellow at the National Academies in 2012 and an NRC Postdoctoral Fellow at the US Naval Research Laboratory from 2014-2016. He joined the Molecular Dynamics Section in the Chemistry Division of NRL as a staff scientist in 2017. Adam was a Jerome and Isabella Karles Fellow at NRL and was awarded the Presidential Early Career Award in Science and Engineering in 2017.