The PI will model the structural and thermodynamic properties of silicate liquids and solids. Liquid simulations will include Monte Carlo and integral equation approaches, with covalent potentials deduced from molecular orbital calculations and spectroscopic as well as thermodynamic data. Properties to be studies include the relationship between glass and liquid structure, Raman and IR spectra of compressed silica glass, equation of state of silicate liquids, and the effect of pressure induced coordination changes on the compressibility. Crystalline phases of selected oxides and silicates will be modelled with Hamiltonians that include many body effects. Parametric many body potentials will be developed in conjunction with numerical models based on extensions of existing electron gas models. The potentials will be used to calculate the elastic constants and phase stability as functions of pressure and temperature. The parametric models will also be used to study relationships among thermal properties and other more easily accessible properties, such as compressibility.
