Three different pathways have been analyzed, by periodic DFT-GGA-LCAO calculations, for the rocksalt-(B1) to CsCl-type (B2) phase transformation of calcium oxide at the equilibrium pressure of 64.7 GPa. The monoclinic P2(1)/m mechanism shows a lower enthalpy barrier (0.13 eV) with respect to the other ones (R (3) over barm and Pmmn), and a secondary minimum in its enthalpy profile gives evidence of a metastable intermediate phase with TlI-like structure and coordination number 7 for both Ca and O. The changes of chemical bonding along the transition path are analyzed.
Catti, M. (2003). Ab initio predicted metastable TlI-like phase in the B1 to B2 high-pressure transition of CaO. PHYSICAL REVIEW. B, CONDENSED MATTER AND MATERIALS PHYSICS, 68(10), 100101-1-100101-4 [10.1103/PhysRevB.68.100101].
Ab initio predicted metastable TlI-like phase in the B1 to B2 high-pressure transition of CaO
CATTI, MICHELE
2003
Abstract
Three different pathways have been analyzed, by periodic DFT-GGA-LCAO calculations, for the rocksalt-(B1) to CsCl-type (B2) phase transformation of calcium oxide at the equilibrium pressure of 64.7 GPa. The monoclinic P2(1)/m mechanism shows a lower enthalpy barrier (0.13 eV) with respect to the other ones (R (3) over barm and Pmmn), and a secondary minimum in its enthalpy profile gives evidence of a metastable intermediate phase with TlI-like structure and coordination number 7 for both Ca and O. The changes of chemical bonding along the transition path are analyzed.
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