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Issue 17, 2015
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Assessing thermochemical properties of materials through ab initio quantum-mechanical methods: the case of α-Al2O3

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Abstract

The thermochemical behavior of α-Al2O3 corundum in the whole temperature range 0–2317 K (melting point) and under pressures up to 12 GPa is predicted by applying ab initio methods based on the density functional theory (DFT), the use of a local basis set and periodic-boundary conditions. Thermodynamic properties are treated both within and beyond the harmonic approximation to the lattice potential. In particular, a recent implementation of the quasi-harmonic approximation, in the Crystal program, is here shown to provide a reliable description of the thermal expansion coefficient, entropy, constant-volume and constant-pressure specific heats, and temperature dependence of the bulk modulus, nearly up to the corundum melting temperature. This is a remarkable outcome suggesting α-Al2O3 to be an almost perfect quasi-harmonic crystal. The effect of using different computational parameters and DFT functionals belonging to different levels of approximations on the accuracy of the thermal properties is tested, providing a reference for further studies involving alumina polymorphs and, more generally, quasi-ionic minerals.

Graphical abstract: Assessing thermochemical properties of materials through ab initio quantum-mechanical methods: the case of α-Al2O3

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Publication details

The article was received on 16 Mar 2015, accepted on 01 Apr 2015 and first published on 01 Apr 2015


Article type: Paper
DOI: 10.1039/C5CP01537E
Author version available: Download Author version (PDF)
Citation: Phys. Chem. Chem. Phys., 2015,17, 11670-11677
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    Assessing thermochemical properties of materials through ab initio quantum-mechanical methods: the case of α-Al2O3

    A. Erba, J. Maul, R. Demichelis and R. Dovesi, Phys. Chem. Chem. Phys., 2015, 17, 11670
    DOI: 10.1039/C5CP01537E

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