Surface energetics of alkaline-earth metal oxides: Trends in stability and adsorption of small molecules

摘要: We present a systematic theoretical investigation of the surface properties, stability and reactivity, rock-salt type alkaline-earth metal oxides including MgO, CaO, SrO, BaO. The accuracy commonly used exchange-correlation density functionals (LDA, PBE, RPBE, PBEsol, BEEF-vdW hybrid HSE) random-phase approximation (RPA) is evaluated compared to existing experimental values. Calculated energies four most stable facets under vacuum conditions: (100) surface, oxygen terminated octopolar (111), (110) surfaces exhibit monotonic increase in from MgO On MgO(100) adsorption CO, NO, CH4 characterized by physisorption while H2O chemisorbs, which agreement with findings. further use on-top CO NO molecules map out energetics each oxide surface. considered all qualitatively predict similar energy trends. ordering between on different can be attributed differences local geometrical structure electronic constituent oxide. striking observation that strength weaker than terraces as period increases, analyzed detail terms charge redistribution within {\sigma} {\pi} channels adsorbates. Finally, we also vacancy formation these systems.