Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation

Ottonello, G.; Civalleri, Bartolomeo; Ganguly, Jibamitra; Perger, Warren F.; Belmonte, Donato; Zuccolini, Marino Vetuschi

doi:10.2138/am.2010.3368

Cited by 51 publications

(54 citation statements)

References 32 publications

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“…Similar expressions can be used to define the average shear modulus, G. 70,71 The computed value of the average bulk modulus is 129 GPa and coincides with the experimental counterpart. As we will discuss below, however, this agreement partially comes from a cancellation of errors due to the fact that zero-point motion and thermal effects are neglected in the calculations while experimental data refer to ambient temperature.…”

Section: A Elastic Anisotropy Under Pressuresupporting

confidence: 64%

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Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Erba

Maul

Pierre

et al. 2015

The Journal of Chemical Physics

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Articles you may be interested inOn combining temperature and pressure effects on structural properties of crystals with standard ab initio techniques J. Chem. Phys. 141, 124115 (2014) We report accurate ab initio theoretical predictions of the elastic, seismic, and structural anisotropy of the orthorhombic Mg 2 SiO 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, firstand 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. C 2015 AIP Publishing LLC. [http://dx

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Section: A Elastic Anisotropy Under Pressuresupporting

confidence: 64%

“…From the knowledge of the elastic tensor, a number of elastic properties can be deduced. [70][71][72] …”

Section: B Elastic Tensor Calculationmentioning

confidence: 99%

Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Erba

Maul

Pierre

et al. 2015

The Journal of Chemical Physics

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“…Magnesium, silicon, aluminum, and oxygen were described by 85-11G(d), 88-31G(d), 85-11G(d), and 8-411G(d) contractions, respectively (McCarthy and Harrison 1994;Catti et al 1994;Nada et al 1996). The exponents of the most diffuse sp and d shells were re-optimized as in our previous investigations to better account for the periodicity of the investigate systems (Ottonello et al 2009a(Ottonello et al , 2009b(Ottonello et al , 2010aBelmonte et al 2013).…”

Section: Methodsmentioning

confidence: 99%

Ab initio thermodynamic and thermophysical properties of sapphirine end-members in the join Mg4Al8Si2O20-Mg3Al10SiO20

Belmonte

Ottonello

Zuccolini

2014

American Mineralogist

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Using the hybrid B3LYP density functional method, we computed the ab initio thermodynamic and thermophysical properties of two sapphirine end-members, Mg 4 Al 8 Si 2 O 20 (sapphirine-442) and Mg 3 Al 10 SiO 20 (sapphirine-351), in the join Mg 3 (Mg 1-X Al X )Al 8 (Al X Si 1-X )SiO 20 with X = 0-1. Static and vibrational calculations performed in the framework of the quasi-harmonic approximation allowed to define the equation of state (EOS), elastic constant tensor, seismic velocities, IR spectra, mode Grüneisen parameters, and thermodynamic properties of both sapphirine end-members. A modified Kieffer's model was adopted to evaluate the optic and acoustic mode contributions to thermodynamic functions stemming from ab initio phonon frequencies and directionally averaged seismic velocities, respectively. The extrinsic stability and liquidus phase relations of sapphirine were investigated in the model system MgO-Al 2 O 3 -SiO 2 (MAS) at different pressure conditions by coupling first-principles calculations with the hybrid polymeric approach (HPA) for multicomponent liquids and minimizing the Gibbs free energy of liquid and solid phases through the convex-hull analysis of equipotential surfaces. According to our thermodynamic modeling, sapphirine turns out to have a small field of primary crystallization in the MAS ternary diagram at 1-bar pressure, which becomes larger due to pressure effects up to 10 kbar, then progressively shrinks and disappears above 21 kbar.

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“…The Mg basis set from Causà et al (1986) was extended by the addition of diffuse sp and d shells (85-11G * contraction). The O basis set of Ottonello et al (2010) was used, modified by the introduction of a d shell (84-11G * contraction) according to Belmonte et al (2014). The Fe basis set is from Valerio et al (1995).…”

Section: Ab-initio Calculationsmentioning

confidence: 99%

Fe-periclase reactivity at Earth’s lower mantle conditions: Ab-initio geochemical modelling

Merli

Bonadiman

Diella

et al. 2017

Geochimica et Cosmochimica Acta

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Thermo-chemical and thermo-physical properties of the high-pressure phase anhydrous B (Mg14Si5O24): An ab-initio all-electron investigation

Abstract: calcoli ab-initio sulle proprietà termodinamiche di fasi stabili ad alta pression

Cited by 51 publications

References 32 publications

Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Structural and elastic anisotropy of crystals at high pressures and temperatures from quantum mechanical methods: The case of Mg2SiO4 forsterite

Ab initio thermodynamic and thermophysical properties of sapphirine end-members in the join Mg4Al8Si2O20-Mg3Al10SiO20

Fe-periclase reactivity at Earth’s lower mantle conditions: Ab-initio geochemical modelling

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