APS virtual seminar: Topical Group on Compression of Condensed Matter

Please join us for an APS Topical Group on Compression of Condensed Matter (GCCM) virtual seminar. Information on the seminar and how to join are below. We would also like to solicit nominations for future seminars and anticipate having a mix of a single speaker or two speakers during an hour time slot. Please email your nominations to Tracy Vogler ([email protected]).

GCCM Virtual Seminar Series Organizing Committee:
Kaleb Burrage, Harrison Horn, Pat Kalita, Tom Lockard, Afreen Syeda, Nenad Velisavljevic, and Tracy Vogler

Click here to register for the seminar and receive the Zoom link.

Polymorphism of Superionic Ice: Static vs Dynamic Compression

Dr. Vitali Pakapenka
Center for Advanced Radiations Sources
The University of Chicago

Date: Thursday, October 17, 2024 at 2 p.m. ET

Abstract:
Water is abundant in natural environments, but its structure and physical properties at ultra extreme conditions remain uncertain. A family of superionic ices with highly mobile protons within the stable oxygen sublattice has been predicted at high pressures in a pressure-temperature phase space that borders the familiar high-pressure solid ices and the fluid. However, the existence of superionic ices, their phase boundaries, and the location of the melting line have been challenging to assess due to the extreme difficulties and uncertainties in both theory and experiments, which yielded contradictory results depending on the techniques applied and data interpretation. Here I will present results of recent measurements on superionic phase boundaries determined at different experimental conditions with extensive comparison to available static and dynamic data including theoretical simulations. Unique properties of superionic phases will be discussed in the light of understanding the pathway of phase transitions in the time-domain experiments.

Biography:
Dr. Pakapenka’s research interests are in the field of the solid-state physics, which is dedicated to understand how extreme conditions (both static and dynamic) affect the physical and chemical properties of materials: structure, phase transition, melting, partitioning, chemical reaction, diffusion, elasticity etc. that can be used for realistic modeling of the composition and dynamics of the terrestrial and giant planet interiors, development of theoretical models. His current primary focus is pushing the limits of ultra-high pressure and temperature experiments to 1 TPa and 10,000 K, which will permit in situ experiments addressing the phase diagrams of compounds relevant to giant planet interiors, light element partitioning between molten iron alloys and silicates, and the synthesis of novel high-pressure materials.

Dr. Prakapenka received his Ph.D. in Solid State Physics from the Moscow Engineering Physics Institut. He was a researcher at the Advanced Materials research Laboratory at the Gomel State University in Belarus. He joined the University of Chicago Center for Advanced Radiation Sources in 2001 and is currently a research professor.