Analysis of a new two-parameter equation of state for MgO

2011 ◽  
Vol 89 (6) ◽  
pp. 709-712 ◽  
Author(s):  
Quan Liu
Keyword(s):  
Numerical Analysis ◽  
Equation Of State ◽  
Bulk Modulus ◽  
Potential Theory ◽  
First Principles ◽  
High Pressures ◽  
Isothermal Bulk Modulus ◽  
Pressure Derivative ◽  
Parameter Equation ◽  
Two Parameter

In this paper, a new two-parameter equation of state (EOS) is developed on the basis of lattice potential theory. The expressions are also obtained for isothermal bulk modulus and its pressure derivative. Numerical analysis is presented for MgO at high pressures (up to 260 GPa) and high temperatures (up to 2000 K). Results based on the new EOS are found to compare well with the corresponding values derived from a first principles approach.

Equation of state and some other properties of rock-salt AlN

2018 ◽  
Vol 6 (1) ◽  
pp. 49
Author(s):  
Salah Daoud ◽  
Rabie Mezouar ◽  
Abdelfateh Benmakhlouf
Keyword(s):  
Heat Capacity ◽  
High Pressure ◽  
Equation Of State ◽  
Bulk Modulus ◽  
Temperature Dependence ◽  
Rock Salt ◽  
Thermophysical Properties ◽  
Constant Pressure ◽  
Isothermal Bulk Modulus ◽  
Pressure Derivative

The object of the present work is to study the equation of state (EOS) and the temperature dependence of the vibrational constant pressure heat capacity, the adiabatic bulk modulus Bs and the pressure derivative of the isothermal bulk modulus of cubic rock-salt Aluminum nitride under high pressure up to 100 GPa. In addition, the isothermal bulk modulus and the Debye temperature θD versus pressure at 1800 K are presented. Some structural and thermophysical properties used here are taken from our previous paper published in J. Electron. Mater. (2018) DOI: 10.1007/s11664-018-6169-x. The results obtained are analyzed and compared with other data of the literature.  

Elastic Constants, Equation of State and Mechanical Relaxations of some Metallic Glasses at High Pressure

2012 ◽  
Vol 706-709 ◽  
pp. 1305-1310
Author(s):  
Masaru Aniya
Keyword(s):  
Equation Of State ◽  
Bulk Modulus ◽  
Elastic Constants ◽  
Metallic Glasses ◽  
High Pressures ◽  
Present Report ◽  
Bulk Metallic Glasses ◽  
Pressure Derivative ◽  
Simple Method ◽  
Murnaghan Equation

One of the fundamental physical quantities necessary to describe the mechanical properties of the materials is the bulk modulus. In the present report, a simple method to estimate the values of the bulk modulus and its pressure derivative of metallic glasses is presented. The method which is based on a jellium model of metals provides a good agreement with measured data. The estimated values of the elastic constants have been used to determine the equation of state of bulk metallic glasses. It is found that the usual Murnaghan equation of state deviates considerably from the experimental results at high pressures. The deviation has been interpreted to arise from the structural relaxations. The effect of pressure on the fragility of bulk metallic glasses is discussed briefly.

Pressure-Volume Behavior of Some Ionic Solids and Geophysical Minerals (CsBr)

2016 ◽  
Vol 28 ◽  
pp. 93-97
Author(s):  
Mehra Mahendra ◽  
Seema Rajput
Keyword(s):  
Experimental Data ◽  
High Pressure ◽  
Equation Of State ◽  
Bulk Modulus ◽  
Phenomenological Equation ◽  
Isothermal Bulk Modulus ◽  
Pressure Derivative ◽  
Ionic Solids ◽  
The Relationship ◽  
Modified Forms

Various forms of the equation of state for studying high-pressure behavior of solids have been developed by numerous investigators using phenomenological approaches. A common feature of the phenomenological equation is that they present the relationship between pressure and volume which can be expressed analytically involving two quantities only, viz Bo, B0’ respectively, the isothermal bulk modulus and its first pressure derivative, both at zero pressure. The present proposal which intend to compare the efficiency of the four equations under close examination reports the V/Vo versus P derived from the new modified forms of Murnaghan equations Birch equation (BE) and Freund-Ingalls (FIE) equation obtained for the best agreement with the available experimental data.

scholarly journals Elastic Behaviour of Diborides Under High Pressure

2009 ◽  
Vol 1 (2) ◽  
pp. 275-280
Author(s):  
Seema Gupta ◽  
S. C. Goyal
Keyword(s):  
High Pressure ◽  
Equation Of State ◽  
Statistical Model ◽  
Bulk Modulus ◽  
Electron Gas ◽  
Elastic Behaviour ◽  
Pressure Derivative ◽  
First Order ◽  
Elastic Data ◽  
Quantum Statistical

The present study deals with the elastic behaviour of diborides (BeB2, MgB2 and NbB2) under high pressure with the help of equation of state (EOS) using the elastic data reported by Islam et al. It is concluded that EOS, which are based either on quantum statistical model or  pseduopotential model, only are capable of explaining high pressure behaviour of the solids under study.  Moreover the value of first order pressure derivative of bulk modulus at infinite pressure (Kinfinity) is greater than 5/3 and thus the diborides under study do not behave as Thomas-Fermi electron gas under high compression. Keywords: Equation of state; High Pressure; Diborides. © 2009 JSR Publications. ISSN: 2070-0237 (Print); 2070-0245 (Online). All rights reserved. DOI: 10.3329/jsr.v1i2.1189 

Structural and Vibrational Properties of Manganese Sulfide

2013 ◽  
Vol 209 ◽  
pp. 186-189
Author(s):  
Brijmohan Y. Thakore ◽  
A.Y. Vahora ◽  
S.G. Khambholja ◽  
A.R. Jani
Keyword(s):  
Bulk Modulus ◽  
Density Functional ◽  
Local Density ◽  
Theoretical Calculations ◽  
Manganese Sulfide ◽  
High Symmetry ◽  
Isothermal Bulk Modulus ◽  
Pressure Derivative ◽  
Density Functional Perturbation Theory ◽  
Quantum Espresso

Structural properties of MnS have been studied using plane wave pseudopotential density functional theory as implemented in Quantum Espresso code. Local density approximation (LDA) along with ultrasoft pseudopotential has been used for total energy calculations. The calculated total energies are fitted to Murnaghan equation of state to calculate equilibrium lattice constant, isothermal bulk modulus and pressure derivative of isothermal bulk modulus for NaCl-type structure of MnS and compared with previous experimental and theoretical calculations and good agreement is achieved with those results. Phonon frequencies have also been derived for B1 phase of MnS along high symmetry directions using the density functional perturbation theory at ambient condition.

Phase transitions of BaCO3 at high pressures

2008 ◽  
Vol 72 (2) ◽  
pp. 659-665 ◽  
Author(s):  
S. Ono ◽  
J. P. Brodholt ◽  
G. D. Price
Keyword(s):  
Phase Transition ◽  
Experimental Study ◽  
High Pressure ◽  
Phase Transitions ◽  
Bulk Modulus ◽  
First Principles ◽  
High Pressures ◽  
Ambient Conditions ◽  
The Stability ◽  
Previous Experimental Study

AbstractFirst-principles simulations and high-pressure experiments were used to study the stability of BaCO3 carbonates at high pressures. Witherite, which is orthorhombic and isotypic with CaCO3 aragonite, is stable at ambient conditions. As pressure increases, BaCO3 transforms from witherite to an orthorhombic post-aragonite structure at 8 GPa. The calculated bulk modulus of the post-aragonite structure is 60.7 GPa, which is slightly less than that from experiments. This structure shows an axial anisotropicc ompressibility and the a axis intersects with the c axis at 70 GPa, which implies that the pressure-induced phase transition reported in previous experimental study is misidentified. Although a pyroxene-like structure is stable in Mg- and Ca-carbonates at pressures >100 GPa, our simulations showed that this structure does not appear in BaCO3.

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