HR: 0800h
AN: T41B-1197    [Abstracts]
TI: Water under extreme conditions of the mantle
AU: * Goncharov, A F
EM: goncharov1@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Goldman, N
EM: goldman14@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Fried, L E
EM: fried1@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Crowhurst, J C
EM: crowhurst1@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Kuo, I W
EM: kuo2@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Mundy, C J
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AU: Zaug, J M
EM: zaug1@llnl.gov
AF: Lawrence Livermore National Laboratory, University of California, 7000 East Avenue, L-372, Livermore, CA 94551 United States
AB: The form in which water exists in the Earth's mantle and crust is currently not very well understood. We used Raman spectroscopy to study fluid water at approximately 1000 K and 2 to 60 GPa in a laser heated diamond anvil cell. First principles molecular dynamics (MD) simulations have also been employed to simulate water at 2000 K up to 120 GPa. The experimental Raman intensity of the O-H stretch mode was observed to decrease with pressure, and beyond 50 GPa this mode was no longer visible. Consistent with this experimental observation, the MD simulations show that water under these conditions consists of very short lived (<10 fs) H$_{2}$O, H$_{3}$O$^{+}$ and O$^{2-}$ species. These results indicate that water at extreme conditions is highly chemically reactive and conductive, which is important for understanding of elementary chemical and physical processes in the Earth.
DE: 8147 Planetary interiors (5430, 5724)
DE: 6045 Physics and chemistry of materials
DE: 3934 Optical, infrared, and Raman spectroscopy
DE: 1060 Planetary geochemistry (5405, 5410, 5704, 5709, 6005, 6008)
SC: Tectonophysics [T]
MN: 2004 AGU Fall Meeting