School of Mechanical and Materials Engineering Seminar Series Presents “Chemistry under Extreme Conditions (XCHEM): Evolution of Chemical Bonding and Crystal Structure of Hot-Dense Solids at Advanced Light Sources” Presented by Dr. Choong-Shik Yoo

About the event

Presented by

Dr. Choong-Shik Yoo, Professor, Department of Chemistry and Institute of Schock Physics, WSU

Abstract

A well-documented body of both experimental and theoretical studies seems to suggest systematic phase/chemical transformations of low Z molecular solids to covalent solids, ionic solids and, eventually, metallic solids under extreme conditions. Inspired by this emerging theme, we have performed an integrated research program of small-scale static and large-scale dynamic high pressure-temperature experiments using synchrotron X-rays, X-ray Free Electron Laser (XFEL) and the National Ignition Facility (NIF), to investigate the evolution of chemical bonding, crystal structure and properties of low Z solids under extreme conditions. In this talk, I will first briefly describe several fundamental principles governing the chemistry of low Z solids under extreme conditions and, then, present our recent results of (i) NIF-Discovery Science Campaign on ramp-compressed NaCl to 1TPa, (ii) MHz time-resolved X-ray diffraction (TR-XRD) at Eu-XFEL to probe the structure evolution of N2 under rapid compression in dynamic-DAC, and (iii) KHz TR-XRD at APS to probe the formation of superionic ice phases under rapid heating in ramp laser-heated DAC.

Biography

Professor Yoo is Professor of Department of Chemistry and Institute for Shock Physics at Washington State University. His research is focused on addressing fundamental materials problems under extreme pressure-temperature conditions, utilizing static and dynamic high-pressure capabilities coupled with the state-of-the-art laser spectroscopic methods and fast time-resolved x-ray diffraction at advanced 3G(synchrotron) and 4G(XFEL) x-rays and  high-power lasers such as National Ignition Facility at the Lawrence Livermore National Laboratory (LLNL). Prior to his arrival at WSU, he worked at the LLNL where he developed and led a large multi-disciplinary research group in High Pressure Physics. Professor Yoo received his Ph.D. in Physical Chemistry in 1986 from UCLA.