HR: 08:32h
AN: MR11A-03 INVITED    [Abstracts]
TI: X-ray induced dissociation of H₂O and formation of an O₂- H₂ compound at high pressure
AU: * Mao, W L
EM: wmao@stanford.edu
AF: Geological & Environmental Sciences and Photon Science, SLAC, Green Earth Sciences Building 367 Panama St., Room 251, Stanford, CA 94305, United States
AU: Mao, H
EM: mao@gl.ciw.edu
AF: Geophysical Laboratory, 5251 Broad Branch Road, NW, Washington, DC 20015,
AU: Mao, H
EM: mao@gl.ciw.edu
AF: HPCAT, Advanced Photon Source Argonne National Laboratory 9700 South Cass Ave., Argonne, IL 60439, United States
AU: Meng, Y
EM: ymeng@hpcat.aps.anl.gov
AF: HPCAT, Advanced Photon Source Argonne National Laboratory 9700 South Cass Ave., Argonne, IL 60439, United States
AU: Eng, P
EM: eng@cars.uchicago.edu
AF: Consortium for Advanced Radiation Sources, 5640 South Ellis Avenue, Chicago, IL 60637, United States
AU: Hu, M Y
EM: mhu@hpcat.aps.anl.gov
AF: HPCAT, Advanced Photon Source Argonne National Laboratory 9700 South Cass Ave., Argonne, IL 60439, United States
AU: Chow, P
EM: pchow@hpcat.aps.anl.gov
AF: HPCAT, Advanced Photon Source Argonne National Laboratory 9700 South Cass Ave., Argonne, IL 60439, United States
AU: Cai, Y Q
EM: cai@nsrrc.org.tw
AF: National Synchrotron Radiation Research Center, 101 Hsin-Ann Road Hsinchu Science Park, Hsinchu, 30076, Taiwan
AU: Shu, J
EM: shu@gl.ciw.edu
AF: Geophysical Laboratory, 5251 Broad Branch Road, NW, Washington, DC 20015,
AU: Hemley, R J
EM: hemley@gl.ciw.edu
AF: Geophysical Laboratory, 5251 Broad Branch Road, NW, Washington, DC 20015,
AB: We observed unexpected radiation chemistry in the ‘simple' H₂O system at high pressure. Beginning with an H₂O sample contained in a diamond anvil cell at high pressure, we found that exposure to the moderately high energy (~10 keV) x-rays used in our x-ray Raman measurements resulted in cleaving of the H₂O molecules, formation of O-O and H-H bonds, and conversion of the O and H framework in ice VII into a new molecular compound composed of O₂ and H₂ molecules. Using a suite of integrated techniques (i.e. x-ray Raman spectroscopy, x-ray diffraction, and optical Raman spectroscopy) we established that this new crystalline solid differs from previously known phases. This new compound remained stable with respect to variations in pressure, temperature, and further x-ray and laser exposure, thus opening new possibilities for studying molecular interactions in the fundamental O₂-H₂ system.
DE: 3924 High-pressure behavior
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 3954 X-ray, neutron, and electron spectroscopy and diffraction
DE: 5422 Ices
SC: Mineral and Rock Physics [MR]
MN: 2007 Fall Meeting