Simultaneous high-pressure and high-temperature volume measurements of ice VII and its thermal equation of state

Article

关键词: DIAMOND-ANVIL CELL;    X-RAY-DIFFRACTION;    HYDROGEN-BOND SYMMETRIZATION;    MELTING CURVE;    CASIO3 PEROVSKITE;    BULK MODULUS;    INFRARED-ABSORPTION;    200 KBAR;    GPA;    H2O;   

DOI  :  10.1103/PhysRevB.82.134103

来源: SCIE

【 摘 要 】

We conducted simultaneous high-pressure (P) and high-temperature (T) unit-cell volume (V) measurements of H2O ice VII in an externally heated diamond anvil cell using in situ synchrotron x-ray diffraction technique with an angle-dispersive system. Isothermal unit-cell volume of ice VII was collected at P = 33-50 GPa with T = 873 K. Nonisothermal experiments at T = 430-740 K and P = 19-37 GPa were also conducted to further constrain P-V-T properties of ice VII. Using the existing 300 K compression data for an equation of state (EoS) at the reference temperature, a thermal EoS of ice VII was constructed from the collected high-P-T data. The melting temperature of ice VII was computed up to P = 40 GPa by thermodynamic calculations with the newly constructed EoS of ice VII. The resulting melting temperatures are higher than that of previous calculations since the new EoS gives a smaller molar volume of ice VII. In contrast, the calculated melting curves are consistent with recent experimental estimates.

【 授权许可】

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