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Title: Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg{sub 2}SiO{sub 4} forsterite

Abstract

We report accurate ab initio theoretical predictions of the elastic, seismic, and structural anisotropy of the orthorhombic Mg{sub 2}SiO{sub 4} forsterite crystal at high pressures (up to 20 GPa) and temperatures (up to its melting point, 2163 K), which constitute earth’s upper mantle conditions. Single-crystal elastic stiffness constants are evaluated up to 20 GPa and their first- and second-order pressure derivatives reported. Christoffel’s equation is solved at several pressures: directional seismic wave velocities and related properties (azimuthal and polarization seismic anisotropies) discussed. Thermal structural and average elastic properties, as computed within the quasi-harmonic approximation of the lattice potential, are predicted at high pressures and temperatures: directional thermal expansion coefficients, first- and second-order pressure derivatives of the isothermal bulk modulus, and P-V-T equation-of-state. The effect on computed properties of five different functionals, belonging to three different classes of approximations, of the density functional theory is explicitly investigated.

Authors:
;  [1];  [1];  [2];  [3]
  1. Dipartimento di Chimica and Centre of Excellence NIS (Nanostructured Interfaces and Surfaces), Università di Torino, via Giuria 5, IT-10125 Torino (Italy)
  2. (Brazil)
  3. Nanochemistry Research Institute, Curtin Institute for Computation, Department of Chemistry, Curtin University, GPO Box U1987, Perth, WA 6845 (Australia)
Publication Date:
OSTI Identifier:
22415875
Resource Type:
Journal Article
Journal Name:
Journal of Chemical Physics
Additional Journal Information:
Journal Volume: 142; Journal Issue: 20; Other Information: (c) 2015 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 0021-9606
Country of Publication:
United States
Language:
English
Subject:
75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; ANISOTROPY; APPROXIMATIONS; DENSITY FUNCTIONAL METHOD; ELASTICITY; EQUATIONS OF STATE; FLEXIBILITY; MAGNESIUM SILICATES; MELTING POINTS; MINERALS; MONOCRYSTALS; ORTHORHOMBIC LATTICES; PHASE DIAGRAMS; POLARIZATION; PRESSURE DEPENDENCE; QUANTUM MECHANICS; SEISMIC WAVES; TEMPERATURE DEPENDENCE; THERMAL EXPANSION

Citation Formats

Erba, A., E-mail: alessandro.erba@unito.it, Dovesi, R., Maul, J., Laboratório de Combustíveis e Materiais, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900 João Pessoa, PB, and De La Pierre, M. Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg{sub 2}SiO{sub 4} forsterite. United States: N. p., 2015. Web. doi:10.1063/1.4921781.
Erba, A., E-mail: alessandro.erba@unito.it, Dovesi, R., Maul, J., Laboratório de Combustíveis e Materiais, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900 João Pessoa, PB, & De La Pierre, M. Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg{sub 2}SiO{sub 4} forsterite. United States. doi:10.1063/1.4921781.
Erba, A., E-mail: alessandro.erba@unito.it, Dovesi, R., Maul, J., Laboratório de Combustíveis e Materiais, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900 João Pessoa, PB, and De La Pierre, M. Thu . "Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg{sub 2}SiO{sub 4} forsterite". United States. doi:10.1063/1.4921781.
@article{osti_22415875,
title = {Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg{sub 2}SiO{sub 4} forsterite},
author = {Erba, A., E-mail: alessandro.erba@unito.it and Dovesi, R. and Maul, J. and Laboratório de Combustíveis e Materiais, INCTMN-UFPB, Universidade Federal da Paraíba, CEP 58051-900 João Pessoa, PB and De La Pierre, M.},
abstractNote = {We report accurate ab initio theoretical predictions of the elastic, seismic, and structural anisotropy of the orthorhombic Mg{sub 2}SiO{sub 4} forsterite crystal at high pressures (up to 20 GPa) and temperatures (up to its melting point, 2163 K), which constitute earth’s upper mantle conditions. Single-crystal elastic stiffness constants are evaluated up to 20 GPa and their first- and second-order pressure derivatives reported. Christoffel’s equation is solved at several pressures: directional seismic wave velocities and related properties (azimuthal and polarization seismic anisotropies) discussed. Thermal structural and average elastic properties, as computed within the quasi-harmonic approximation of the lattice potential, are predicted at high pressures and temperatures: directional thermal expansion coefficients, first- and second-order pressure derivatives of the isothermal bulk modulus, and P-V-T equation-of-state. The effect on computed properties of five different functionals, belonging to three different classes of approximations, of the density functional theory is explicitly investigated.},
doi = {10.1063/1.4921781},
journal = {Journal of Chemical Physics},
issn = {0021-9606},
number = 20,
volume = 142,
place = {United States},
year = {2015},
month = {5}
}