Research to Produce Pressures of 450 GPa or Higher on Hydrogen and to Produce Metallic Hydrogen

Cornell University, Ithaca NY

Investigators

Abstract

This project concerns attempts to statically compress hydrogen to pressures of 450 GPa or higher. Hydrogen has multifaceted behavior, exhibiting covalent bonding in the molecule, behaving as a positive ion combined with H2O (HCl in water), as a negative ion (in large part) in crystals of the alkali hydrides, and having secondary hydrogen bonds with electronegative elements already bonded to other molecules. Quantum mechanical calculations performed by Wigner and Huntington in 1935 showed that still another possibilty exists, namely that at very high pressures hydrogen could be metallic. A more recent prediction suggests that metallic hydrogen could be a high temperature superconductor. This goal of this project is to realize the metallic state of hydrogen by static compression. The realization of this goal will solve one of the outstanding problems of condensed matter physics. It will open up new areas of investigation of the properties of materials under extreme conditions of pressure and will assist in the understanding of the cores of the giant planets which are believed to be composed of metallic hydrogen. %%% Since the early 1900s hydrogen has been the key element for the understanding of the structure of matter. Hydrogen has multifaceted behavior. It exhibits covalent bonding to form a molecule, it behaves as a positive ion combined with water, it exists in large part as a negative ion in crystals of the alkali hydrides, etc.. Quantum mechanical calculations performed in 1935 showed that still another possibility exists, namely that at very high pressures hydrogen could be metallic, while a more recent prediction suggests that metallic hydrogen could even be a high temperature superconductor. It is the goal of this research to generate sufficiently high static pressures to bring about an experimentally verifiable state of metallic hydrogen. The pressures necessary to accomplish this have never been achieved in the laboratory but are believed to exist in the cores of the giant planets. The realization of this goal will open up new areas of investigation of the properties of materials under extreme conditions of pressure, and will provide data needed for the understanding of the properties of the cores of the giant planets. ***