Dr. Viktor Struzhkin [from Geophysical Laboratory of the Carnegie Institution]

Title: New Chemistry of Alkali Metal Hydrides and Compressed Hydrogen: Polyhydrides of Sodium
Time: 14:00 - 15:00, December 10
Place: Conference Room 201, Building 6, HPSTAR (Shanghai)
Host: Xiaojia Chen

Abstract:
The only known compound of sodium and hydrogen is archetypal ionic NaH. Application of high pressure is known to promote states with higher atomic coordination, but extensive search for polyhydrides with unusual stoichiometry remains unsuccessful in spite of several theoretical predictions. We combined synchrotron x-ray diffraction and Raman spectroscopy in a laser heated diamond anvil cell and theoretical ab-initio random structure search, which both agree in stable structures and compositions. Our results support the formation of multicenter bonding (three center units such as H3-) and polyhydride materials with unusual stoichiometry. These results open a new family of hydrides for exploration of novel chemistry of hydrides and new routes to superconductivity in hydrogen–rich solids.

Biography of the Speaker:
Viktor V. Struzhkin was awarded combined BSc and MSc degrees in physics from Moscow Institute of Physics and Technology, Russia in 1980. After that, he moved to Institute for High Pressure Physics, Russian Academy of Science and obtained a Ph.D in solid-state physics in 1991. He is now a senior staff scientist of Geophysical Laboratory of the Carnegie Institution for Science since 2003. At the Carnegie, he pioneered a suit of transport measurements in diamond anvil cells succeeding in measurements of superconductivity at very high pressures in excess of 200 GPa (2 million atmospheres). He is recognized expert in a multitude of experimental techniques in diamond anvil cells, including transport measurements, optical and synchrotron spectroscopy. His research interests cover condensed-matter physics, simple molecular solids, the chemistry and physics of the Earth’s mantle and core, and high-pressure materials science. He has published nearly 200 papers in journals like Nature, Science, Chemical Review, and Physical Review Letters with over 6000 citations, contributing h-index of 42.