Size-Consistent Adiabatic Connection Functionals and Applications to Metallic Systems

The adiabatic connection formula can be used to interpolate the correlation energy between a weak interaction limit described by many-body perturbation theory and a strong interaction limit approximated by density functionals. This provides a balanced description of different correlation effects. However, because this interpolation is nonlinear, achieving size-consistency with the models can be challenging. In this talk, we discuss our recently developed method for implementing adiabatic connection functionals in a size-consistent manner, called orbital-based size-consistent matrix interpolation (OSMI). When paired with a simple adiabatic connection model and the point charge plus continuum model for strictly correlated electrons, OSMI achieves excellent accuracy for the barrier heights of molecular reactions and reproduces the correlation energy of the uniform electron gas at high, low, and intermediate densities. Building on these initial results, we apply the OSMI approach to bulk metallic systems and assess its accuracy.