HR: 10:20h
AN: MR12A-01    [Abstracts]
TI: First Principles Investigation of Liquid MgO at High Pressure
AU: Bhattarai, D
EM: dipesh@csc.lsu.edu
AF: Department of Computer Science, Louisiana State University, 298 Coates Hall, Baton Rouge, LA 70803 United States
AU: * Karki, B B
EM: karki@csc.lsu.edu
AF: Department of Computer Science, Louisiana State University, 298 Coates Hall, Baton Rouge, LA 70803 United States
AU: Stixrude, L
EM: stixrude@umich.edu
AF: Department of Geological Sciences, University of Michigan, 2534 CC Little Building, 1100 N. University Ave., Ann Arbor, MI 48109 United States
AB: We have investigated the structural, dynamic and electronic properties of liquid MgO at realistic mantle pressure and temperature conditions using a combintation of computational and visualization methods. First principles molecular dynamics (FPMD) simulations are performed within the framework of density functional theory and pseudopotential approximation. Several macroscopic properties of interest including the equation of state, heat capacity and Gruneisen parameter are derived. The simulated time-dependent 3D datasets for the atomic positions and electronic charge densites are analyzed with an interactive visualization system which is under development. The analysis shows that the liquid structure is highly sensitive to compression, for instance, the Mg-O coordination number increases from 5 at zero pressure to 7 at high pressure. The calculated diffusion coefficient decreases with compression and increases with temperatures. The atomistic diffusion process appears to be non-uniform among the constituent atoms. The electronic properties of the liquid phase are shown to differ substantially from those of the crystalline phase.
DE: 1042 Mineral and crystal chemistry (3620)
DE: 1043 Fluid and melt inclusion geochemistry
DE: 3672 Planetary mineralogy and petrology (5410)
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
SC: Mineral and Rock Physics [MR]
MN: Fall Meeting 2005