Effect of exchange and correlation on bulk properties of MgO, NiO, and CoO

Bulk properties of the isostructural oxides MgO, NiO, and CoO have been cal culated quantum chemically with periodic models and compared with experimen tal data from the literature. Ab initio Hartree-Fock, gradient-corrected de nsity-functional methods, and hybrid approaches have been used for the calc ulation of the lattice constants, heats of atomization, and electronic stru ctures. General trends of the effects of electron correlation and the treat ment of exchange on the calculated properties are observed. None of the sta ndard methods considered provided results in agreement with experimental da ta for all properties. A combination of Becke's three-parameter exchange fu nctional and the Lee-Yang-Parr correlation functional (B3LYP) leads to a co nsistent description of the electronic and structural properties in compara tive studies of the three compounds. Other methods are more accurate than B 3LYP if certain properties or compounds are considered. The combination of the Hartree-Fock exchange functional with the Lee-Yang-Parr density-functio nal correlation is the best method for the open-shell transition-metal oxid es NiO and CoO in terms of relative stability and geometry and the electron ic structure of the valence band. The absolute values of calculated heats o f atomization, however, are generally too small. The density-functional met hod based on the Perdew-Wang generalized gradient approximation (PWGGA) is preferable for the calculation of thermodynamic properties for all compound s but is less reliable in the prediction of structural and electronic prope rties. A hybrid approach based on the PWGGA method is proposed that improve s the results for bulk geometries and electronic properties while maintaini ng the high quality of calculated energetic results.