Speaker: Dr. Haiwang Yong, University of California, Irvine

Host: Prof. Yutong Li, Key Laboratory of Optical Physics, Institute of Physics

Time: 10:00 am, December 8th, 2022

Abstract:

Quantum coherence in molecules (i.e. vibrational, electronic and vibronic coherences) plays a critical role in determining the pathways and outcomes of virtually all photophysical and photochemical molecular processes. Novel beam sources like x-ray free electron lasers (XFELs) have unprecedented brilliance, tunability, and time resolution, offering new capabilities for probing fundamental coherence phenomena in molecules. In this talk, I will discuss recent experimental advances in ultrafast x-ray scattering where we exploit ultrashort hard x-ray pulses of the Linac Coherent Light Source (LCLS) to study ultrafast structural dynamics in molecules, including direct measurement of the vibrational coherence and dephasing in an excited-state polyatomic molecule, and observation of nearly-instant changes in electron density upon photoexcitation. I will then discuss future opportunities such as capturing vibronic coherences at conical intersections and real-space imaging of attosecond charge migration.

Brief CV of Dr. Haiwang Yong:

Dr. Haiwang Yong is a postdoctoral scholar in Prof. Shaul Mukamel’s lab at the University of California, Irvine since 2021. He received his B.S. degree in physics from the University of Science and Technology of China (USTC) in 2016 and obtained his PhD degree in physical chemistry from Brown University (advisor: Prof. Peter M. Weber) in 2021. His research interests include ultrafast x-ray science, ultrafast electron diffraction, structural dynamics and electron dynamics. He was selected as a finalist in the 2021 LCLS Young Investigator Award by SLAC National Accelerator Laboratory, and he and his collaborators were awarded the 2021 Horizon Prize by the Royal Society of Chemistry.