The ground-state crystal energies of cubic MgAl2O4 (spinel) and MgO (periclase) and of rhombohedral alpha-Al2O3 (corundum) have been calculated at different volumes, relaxing the corresponding structures, by all-electron periodic Hartree-Fock methods (CRYSTAL program). Basis sets of contracted Gaussian-type functions are employed for the 18 atomic (including d) orbitals representing each of the Mg, Al, and O atoms. Mulliken net atomic charges z(Mg)=1.86\e\ (MgO), z(Al)=2.30\e\ (alpha-Al2O3), z(Mg)=1.74\e\, and z(Al) = 2.24\e\ (spinel) are obtained. The elastic bulk modulus, the Murnaghan equation of state p(V) at the athermal limit, the Mg-O and Al-O bond compressibilities, and the binding energy have been derived for each phase (and the elastic constants C-11 and C-12 for spinel only). Comparison with existing experimental data is discussed. The enthalpy change for spinel decomposition into the simple oxides has been computed as a function of pressure, including a correction for the electron correlation energy based on local-density-functional theory. A decomposition pressure of 11 GPa at T=0 K is predicted, against values of 8 and 13 GPa derived from experimental thermodynamic data and from direct compression experiments, respectively.

Quantum-mechanical Calculation of the Solid-state Equilibrium Mgo+alpha-al2o3-reversible-arrow-mgal2o4 (spinel) Versus Pressure / M., Catti; G., Valerio; R., Dovesi; Causa', Mauro. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 49:(1994), pp. 14179-14187. [10.1103/PhysRevB.49.14179]

Quantum-mechanical Calculation of the Solid-state Equilibrium Mgo+alpha-al2o3-reversible-arrow-mgal2o4 (spinel) Versus Pressure

CAUSA', Mauro
1994

Abstract

The ground-state crystal energies of cubic MgAl2O4 (spinel) and MgO (periclase) and of rhombohedral alpha-Al2O3 (corundum) have been calculated at different volumes, relaxing the corresponding structures, by all-electron periodic Hartree-Fock methods (CRYSTAL program). Basis sets of contracted Gaussian-type functions are employed for the 18 atomic (including d) orbitals representing each of the Mg, Al, and O atoms. Mulliken net atomic charges z(Mg)=1.86\e\ (MgO), z(Al)=2.30\e\ (alpha-Al2O3), z(Mg)=1.74\e\, and z(Al) = 2.24\e\ (spinel) are obtained. The elastic bulk modulus, the Murnaghan equation of state p(V) at the athermal limit, the Mg-O and Al-O bond compressibilities, and the binding energy have been derived for each phase (and the elastic constants C-11 and C-12 for spinel only). Comparison with existing experimental data is discussed. The enthalpy change for spinel decomposition into the simple oxides has been computed as a function of pressure, including a correction for the electron correlation energy based on local-density-functional theory. A decomposition pressure of 11 GPa at T=0 K is predicted, against values of 8 and 13 GPa derived from experimental thermodynamic data and from direct compression experiments, respectively.
1994
Quantum-mechanical Calculation of the Solid-state Equilibrium Mgo+alpha-al2o3-reversible-arrow-mgal2o4 (spinel) Versus Pressure / M., Catti; G., Valerio; R., Dovesi; Causa', Mauro. - In: PHYSICAL REVIEW. B, CONDENSED MATTER. - ISSN 0163-1829. - STAMPA. - 49:(1994), pp. 14179-14187. [10.1103/PhysRevB.49.14179]
File in questo prodotto:
Non ci sono file associati a questo prodotto.

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11588/488977
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus ND
  • ???jsp.display-item.citation.isi??? 172
social impact