Mbar Chemistry: Novel States of Matter at Extreme Conditions

Washington State University, Pullman WA

Investigators

Abstract

TECHNICAL SUMMARY: Application of high pressure significantly alters the interatomic distance and, thus, the nature of intermolecular interaction, chemical bonding, molecular configuration, crystal structure, and stability of solid. With modern advances in high-pressure technologies, it is feasible to achieve a large (often up to a several-fold) compression of lattice, at which condition material can be easily forced into a new physical and chemical configuration. The high-pressure thus offers enhanced opportunities to discover new phases, both stable and metastable ones, and to tune novel properties in a wide-range of atomistic length scale, substantially greater than (often being several orders of) those achieved by other thermal (varying temperatures) and chemical (varying composition or making alloys) means. The goal of this proposed work is to investigate new states of matter and novel phenomena occurring in simple low-Z molecules like carbon dioxide and nitrogen at Mbar pressures. Commonly observed at these conditions are metallic and nonmetallic extended solids that can store a large sum of energy in their three-dimensional network structures. Yet, a large cohesive energy of low Z solids gives rise to an extremely stiff lattice and novel electronic and optical properties. Broadly speaking, these molecular-to-nonmolecular transitions occur due to electron delocalization manifested as a rapid increase in electron kinetic energy at high density, but there are many outstanding questions regarding the exact nature of chemical bonding, phase stability, and chemical mechanisms. Many of the questions are fundamental problems in solid state chemistries and condensed matter physics, which will be addressed in this project. NON-TECHNICAL SUMMARY: The research outlined in this proposal will impact fundamental solid-state chemistries and condensed materials sciences, which will eventually establish new Periodic orders of elements and solids at Mbars. The project will also have significant impacts on training graduate and undergraduate students by providing hands-on research experiences in cutting-edge experimental technologies at Washington State Univerisity (WSU) and at synchrotron facilities and national laboratories. The present study will bring the excitement of high-pressure materials research to the scientists and students in Spokane and nearby areas well beyond the WSU and, thus, enhance public appreciation of the relevance of fundamental materials research to the future and society. Hence, the benefits of the project reach well beyond the immediate scientific scope of this proposal.