Stability of MgAl 2 O 4 Under High-Pressure Conditions |
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| Authors: | A Beltrán L Gracia J Andrés R Franco J M Recio |
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| Institution: | 1. Departament de Ciències Experimentals , Universitat Jaume I , Castelló , E-12080 , Spain Fax: E-mail: beltran@exp.uji.es;2. Departament de Ciències Experimentals , Universitat Jaume I , Castelló , E-12080 , Spain;3. Departamento de Química Física y Analítica , Universidad de Oviedo , Oviedo , E-33006 , Spain |
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| Abstract: | A theoretical investigation of the MgAl 2 O 4 crystal response to high-pressure conditions has been carried out to determine its stability against decomposition towards MgO and f -Al 2 O 3 , and towards recently observed orthorhombic phases. We have evaluated total energy versus volume curves using the density functional formalism under the non-local B3LYP approximation, as implemented in the CRYSTAL package. Numerical and analytical fittings have been carried out to determine the equilibrium unit cell geometry and equation of state parameters for all the structures and compounds involved in the phase diagram. The macroscopic compressibility of the spinel phase is interpreted considering the compressibility of its elementary MgO 4 and AlO 6 coordination polyhedra, and implications to understand the phase stability are suggested. |
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| Keywords: | Mgal2o4 Crystal Coordination Polyhedra High-pressure Equation Of State Phase Transitions Ab Initio Calculations |
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