HR: 11:35h
AN: MR12A-06    [Abstracts]
TI: Structures and Densities of Non-Crystalline Materials at High Pressures and Temperatures
AU: * Shen, G
EM: gshen@hpcat.aps.anl.gov
AF: HPCAT-Advanced Photon Source, 9700 S Cass Ave Bldg 434E Argonne National Lab, Argonne, IL 60439 United States
AB: With the development of synchrotron facilities, direct measurements on structures and densities of non-crystalline materials become feasible at high pressures and high temperatures. Information on the local structure (microscopic data) provides a basis for understanding numerous macroscopic properties such as elasticity and viscosity. Densities of molten materials have important implications for the dynamics and evolution of the Earth and other planets. We report results on (1) amorphous iron at high pressures and room temperature, (2) SiO₂ and MgSiO₃ glasses at high pressures and room temperature, and (3) liquid iron at high pressures and high temperatures. The experiments were performed using a modified diamond anvil cell that allows measurements of x-ray scattering with large momentum coverage. The measurements were performed at the GSECARS at the Advanced Photon Source. Those results demonstrate the feasibility of structural determination on amorphous materials in a DAC to ultra high pressures. The accuracy of density determination for non-crystalline materials is found to be within 1.5%, compared to about 0.2% for crystalline materials with the x-ray diffraction method.
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1212 Earth's interior: composition and state (7207, 7208, 8105, 8124)
DE: 3630 Experimental mineralogy and petrology
DE: 3694 Instruments and techniques
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005