| Popis: |
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. |
