HR: 0800h
AN: DI41A-0340    [Abstracts]
TI: New P-V-T equation of state is proposed and tested against experiments on perovskite and epsilon iron
AU: * Garai, J
EM: jozsef.garai@fiu.edu
AF: Florida International University, University Park, PC 344, Miami, FL 33199,
AB: The volume is not an independent variable and must be broken down into its fundamental components when the relationships to the pressure and temperature are defined. Using absolute reference frame (zero pressure and temperature) three initial parameters, the volume at zero pressure and temperature, the bulk modulus at zero temperature, and the volume coefficient of thermal expansion at zero pressure are defined. It is assumed that the temperature derivative of the bulk modulus is zero, and that the pressure derivative of the volume coefficient of thermal expansion is constant. The pressure dependence of the bulk modulus is described by linear and exponential factors and linear change for the temperature derivative of the volume coefficient of thermal expansion is assumed. Based on these assumptions a new EoS consisting seven parameters is derived. The new EoS is tested against the experiments on perovskite and epsilon iron. The Root-mean-square- deviations (RMSD) of the residuals of the molar volume, pressure, and temperature are 0.043 cm³, 0.8 GPa, and 128 K for perovskite and 0.018 cm³, 1.7 GPa, and 117 K for iron respectively. The RMSD values indicate that the new EOS is able to reproduce the data within the uncertainties of the experiments. Separating the experiments into 200 K ranges the new EoS was compared to the most widely used finite strain, interatomic potential, and empirical isothermal EoSs such the Birch-Murnaghan, the Vinet, and the Roy-Roy respectively. Correlation coefficients, RMSD of the residuals and Akaike Information Criteria are used to evaluate the fit. Based on these fitting parameters the new p-V-T EoS is superior in every temperature range to all of the investigated conventional isothermal EoSs for both perovskite and epsilon iron. The new EoS of epsilon iron reproduces the PREM densities at 4400 K indicating that the melting temperature of iron is around 4400 K at the outer-inner core boundary and that presence of light elements might not be necessary to explain the inner core densities.
UR: http://www.garai-research.com
DE: 3919 Equations of state
DE: 3924 High-pressure behavior
DE: 7207 Core (1212, 1213, 8124)
DE: 8115 Core processes (1213, 1507)
DE: 8124 Earth's interior: composition and state (1212, 7207, 7208, 8105)
SC: Study of the Earth's Deep Interior [DI]
MN: 2007 Fall Meeting