Phonon Density of States and Compression Behavior in Iron Sulfide under Pressure

Argonne National Laboratory, Lemont, Illinois, United States
Physical Review Letters (Impact Factor: 7.51). 12/2004; 93(19):195503. DOI: 10.1103/PhysRevLett.93.195503
Source: PubMed


We report the partial phonon densities of states (DOS) of iron sulfide, a possible component of the rocky planet's core, measured by the 57Fe nuclear resonant inelastic x-ray scattering and calculate the total phonon DOS under pressure. From the phonon DOS, we drive thermodynamic parameters. A comparison of the observed and estimated compressibilities makes it clear that there is a large pure electronic contribution in the observed compressibility in the metallic state. Our results present the observation of thermodynamic parameters of iron sulfide with the low-spin state of an Fe2+ ion at the high density, which is similar to the condition of the Martian core.

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    • "Fits to the data provide the curvature of the parabola defined by Equa tion 9, and with the known density, one can derive Debye sound velocities of 3.49(5) km/s for ambient conditions, 4.54(6) km/s for 50 GPa and 300 K, and 3.98( I) km/s for 55 GPa and 1500 K, where values in paranthesis represent standard errors. In a similar way, Debye sound velocities have been obtained for iron metal (Mao et al., 2001), Fe-Ni and Fe-Si alloys (Lin et al., 2003), Fe09jrO (Struzhkin et al., 2001), Fe3S (Lin et al., 2004a), FeHv (Mao et al., 2004b), and FeS (Kobayashi et al., 2004) under high pressure. Very recently, the same method was applied to measure "
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