CSEDI: Theoretical and Experimental Studies of Some Materials Fundamental to the Deep Mantle

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Duffy 0112532 The investigators will develop new theoretical techniques and conduct new high pressure and temperature experiments to examine the melting curves, crystal structures, and high-temperature equations of state (EOS) of the following materials: MgO, SiO2, MgSiO3, and Au. They will accomplish this by developing a major extension of the density functional theory - molecular dynamics (DFT-MD) method and applying it to minerals of the Earth's deep mantle. The approach is to develop empirical "optimal" potentials from the results of a DFT-MD simulation. This optimal potential can then be used in further calculations involving much larger systems and longer run durations. From this, the investigators can determine crystal structures, melting curves, liquid viscosities, compressibilities, elastic constants and other thermoelastic properties directly at lower mantle P-T conditions. They will also carry out detailed comparison of their simulation results with laser-heated synchrotron experiments on MgO, SiO2, and Au to assess the reliability of the OP method. In particular, they will focus on measurements of melting curves of these materials at high pressure to provide a sensitive test of the optimal potential calculations.