HR: 1340h
AN: MR13A-0069    [Abstracts]
TI: Solid-state Amorphization and Melting of Silica Stishovite: the Effect of Defects
AU: * Luo, S
EM: sluo@gps.caltech.edu
AF: Sheng-Nian Luo, P-24 Plasma Physics, Los Alamos National Laboratory, Los Alamos, NM 87544 United States
AU: Zheng, L
EM: zhengl@missouri.edu
AF: Lianqing Zheng, Department of Chemistry, University of Missouri-Columbia, Columbia, MO 65211 United States
AU: Tschauner, O
EM: olivert@physics.unlv.edu
AF: Oliver Tschauner, igh-Pressure Science and Engineering Center and Department of Physics, University of Nevada, Las Vegas, NV 89154 United States
AB: We investigate spontaneous and heating-driven disordering of metastable stishovite at ambient pressure, and the effect of defects using molecular dynamics simulations. Melting may precede solid-state amorphization for stishovite with small concentrations of defects. However, if sufficiently defected, amorphization occurs prior to melting for the structures with grain boundaries, vacancies and free surfaces. Melting of the amorphized solid is continuous, in sharp contrast to glass for which melting is sluggish yet evidently first-order. Amorphization on free surfaces is anisotropic, being more pronounced on (101), (011) and (111) than on (100), (010), (001) and (110) crystallographic planes. *Work partly performed under the auspices of the U.S. Department of Energy under contract No. W-7405-ENG-36 and NNSA Cooperative Agreement DE-FC88-01NV14049.
DE: 0545 Modeling (4255)
DE: 3654 Ultra-high pressure metamorphism
DE: 3904 Defects
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005