First-principles theory for the equations of state of minerals at high pressures and temperatures: Application to MgO

1985 ◽  
Vol 12 (5) ◽  
pp. 247-250 ◽  
Author(s):  
R. J. Hemley ◽  
M. D. Jackson ◽  
R. G. Gordon
Keyword(s):  
First Principles ◽  
High Pressures ◽  
Equations Of State ◽  
High Pressures And Temperatures

Wide-range equations of state for organic liquids

2007 ◽  
Vol 5 ◽  
pp. 113-120 ◽  
Author(s):  
R.Kh. Bolotnova
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
Organic Liquids ◽  
Liquid Phases ◽  
Wide Range ◽  
High Pressures And Temperatures

The method of construction the wide-range equations of state for organic liquids, describing the gas and liquid phases including dissociation and ionization which occurs during an intense collapse of steam bubbles and accompanied by ultra-high pressures and temperatures, is proposed.

First-principles modelling of Earth and planetary materials at high pressures and temperatures

2006 ◽  
Vol 69 (8) ◽  
pp. 2365-2441 ◽  
Author(s):  
M J Gillan ◽  
D Alfè ◽  
J Brodholt ◽  
L Vočadlo ◽  
G D Price
Keyword(s):  
First Principles ◽  
High Pressures ◽  
High Pressures And Temperatures ◽  
Planetary Materials

THERMODYNAMIC PROPERTIES OF MgSiO3 POST-PEROVSKITE

2010 ◽  
Vol 24 (03) ◽  
pp. 315-324
Author(s):  
ZI-JIANG LIU ◽  
XIAO-WEI SUN ◽  
CAI-RONG ZHANG ◽  
LI-NA TIAN ◽  
YUAN GUO
Keyword(s):  
Thermodynamic Properties ◽  
First Principles ◽  
Density Functional ◽  
High Pressures ◽  
Local Density ◽  
Harmonic Approximation ◽  
Debye Model ◽  
Functional Theory ◽  
High Pressures And Temperatures ◽  
First Time

The thermodynamic properties of MgSiO 3 post-perovskite are predicted at high pressures and temperatures using the Debye model for the first time. This model combines with ab initio calculations within local density approximation using pseudopotentials and a plane wave basis in the framework of density functional theory, and it takes into account the phononic effects within the quasi-harmonic approximation. It is found that the calculated equation of state of MgSiO 3 post-perovskite is in excellent agreement with the latest observed values. Based on the first-principles study and the Debye model, the thermal properties including the Debye temperature, the heat capacity, the thermal expansion, and the entropy are obtained in the whole pressure range from 0 to 150 GPa and temperature range from 0 to 2000 K.

scholarly journals Equations of state in the Fe-FeSi system at high pressures and temperatures

2014 ◽  
Vol 119 (4) ◽  
pp. 2810-2827 ◽  
Author(s):  
Rebecca A. Fischer ◽  
Andrew J. Campbell ◽  
Razvan Caracas ◽  
Daniel M. Reaman ◽  
Dion L. Heinz ◽  
...  
Keyword(s):  
High Pressures ◽  
Equations Of State ◽  
High Pressures And Temperatures

scholarly journals Limits to the Validity of Thermal-Pressure Equations of State

Minerals ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 562 ◽  
Author(s):  
Ross J. Angel ◽  
Francesca Miozzi ◽  
Matteo Alvaro
Keyword(s):  
Phonon Mode ◽  
High Pressures ◽  
Static Pressure ◽  
Equations Of State ◽  
Harmonic Approximation ◽  
Rapid Decrease ◽  
Combined Effects ◽  
Thermal Pressure ◽  
Reference Volume ◽  
High Pressures And Temperatures

Thermal-pressure Equations of State (EoS) such as the Mie-Grüneisen-Debye (MGD) model depend on several assumptions, including the quasi-harmonic approximation (QHA) and a simplified phonon density of states. We show how the QHA is violated by materials exhibiting anisotropic thermal pressure. We also show that at pressures lower than those of the isochor of the reference volume, the static pressure may become sufficiently negative to make the compressional part of the EoS invalid. This limit is sensitive to the combined effects of the EoS parameters K’0, q and the Grüneisen parameter γ0. Large values of q, which correspond to a rapid decrease in phonon mode frequencies with increasing volume, can also lead to the bulk modulus becoming zero at high pressures and temperatures that are not particularly extreme for planetary geotherms. The MGD EoS therefore has an extremely limited P and T regime over which it is both valid and has physically-meaningful properties. Outside of this range, additional terms should be included in the thermal pressure that represents the physical properties of the solid. Or, alternatively, ‘isothermal’ EoS in which the temperature variation of the elastic properties is explicitly modeled without reference to a physical model can be used.

First-Principles Modelling of Earth and Planetary Materials at High Pressures and Temperatures

ChemInform ◽  
2007 ◽  
Vol 38 (34) ◽  
Author(s):  
M. J. Gillan ◽  
D. Alfe ◽  
J. Brodholt ◽  
L. Vocadlo ◽  
G. D. Price
Keyword(s):  
First Principles ◽  
High Pressures ◽  
High Pressures And Temperatures ◽  
Planetary Materials
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