Formation energies of group I and II metal oxides using random phase approximation

The enthalpy of formation for 23 metal oxides, which include groups I and II as well as two transition metals (Ti and Ru), are calculated using random phase approximation (RPA). Compared to the PBE xc functional, the RPA reduces the mean absolute error (MAE) per oxygen from 0.44 to 0.15 eV. The calculated deviations from experiments are separated into two parts: a systematic and uniform error related to the reference energy of O and the errors specific to diffferent oxidation states O^2-, O₂^2-, and O₂^-. Our results show that the RPA improves both the reference energy and the three oxidation states.