Novel xenon-hydrogen compound forms under pressure

1. Novel xenon-hydrogen compound forms under pressure Russell J. Hemley (Carnegie Institution of Washington) DMR 0508988 Unexpected molecular condensed matter chemistry has been uncovered in xenon-hydrogen mixtures under pressure. A molecular compound Xe(H2)6 has been identified and characterized by a suite of laser-based and synchrotron-based diamond-anvil cell techniques at APS and NSLS. The compound is stable to above 2 million atmospheres pressures (200 GPa) where it forms a very high-density molecular semiconductor. These studies open avenues to discovering new classes of compounds, explorations of new routes for metallization of hydrogen, and tests of fundamental tenets of condensed matter theory in simple molecular systems. Structure of Xe(H2)6. The blue balls are molecules of hydrogen which can be visualized as freely rotating dumbbells while the red spheres are xenon atoms. Somayazulu et. al, Phys. Rev. Lett., submitted

2. Novel xenon-hydrogen compound forms under pressure Russell J. Hemley (Carnegie Institution of Washington) DMR 0508988 Studies of new hydrogen-rich molecular mixtures are driven by both the search for novel hydrogen storage systems and the quest for metallic hydrogen. This work is providing a window into a new world of what happens to molecules under very high pressures. The research makes extensive use of major national synchrotron facilities for x-ray diffraction (APS) and infrared spectroscopy (NSLS). As such, the work has enhanced collaboration between academia and national labs with training of students and post-doctoral fellows in new techniques. Technologically, these studies open the possibility of new families of hydrogen storage materials and possible novel metals and even superconductors. The results have implications for the solubility of heavy elements in gas giant planets. X-ray measurements at HPCAT, APS, ANL Synchrotron Infrared spectra of H2 vibrations at U2A,NSLS, BNL