ELASTIC-CONSTANTS, PHASE-TRANSITION, AND ELECTRONIC-STRUCTURE OF STRONTIUM OXIDE SRO - AN AB-INITIO HARTREE-FOCK STUDY

The static structural properties and B1-B2 phase transition of SrO were calculated at an ab initio level within the Hartree-Fock (HF) approximation using the effective core potential. The HF data were corrected a posteriori by integrating the HF charge density according to the correlation-only gradient-density-functional formulas proposed by Colle and Salvetti [Theor. Chim. Acta 37, 329 (1975)] and by Perdew [J.P. Perdew et al., Phys. Rev. B 46, 6671 (1992)]. The HF binding energy, structural parameters, lattice parameter, bulk modulus, and elastic constants are in reasonable agreement with experiment. The correlation correction brings the binding energy into better agreement with the experiment. The transition pressure between B1 and B2 phases is in good agreement with the experimental value at the HF level, whereas it is corrected poorly by the addition of an a posteriori correlation correction.