Screened Coulomb interactions of localized electrons in transition metals and transition-metal oxides

The screened Coulomb interactions of localized electrons, often treated as adjustable parameters in constructing model Hamiltonians, are important quantities for studying strongly correlated materials. Using a recently implemented constrained random phase approximation approach, we have calculated the screened Coulomb and exchange interactions of 3d electrons in transition metals, late transition-metal monoxides, and VO2. For monoxides, we have also calculated the on-site screened Coulomb interaction for oxygen p electrons as well as the intersite pd interaction. Our results compare reasonably well with available experimental and theoretical results. We find that for oxide systems, a self-consistent procedure is very important for an accurate account of the screening effect.