Accurate and robust wavefunction embedding methodologies

Abstract

We describe embedded d. functional theory (e-DFT) methods that avoid approxns. to the kinetic energy functional and provide a formally exact approach to performing electronic structure calcns. in the e-DFT framework. This framework allows systems to be divided into smaller subsystems which can be treated at different levels of theory, with the inter-subsystem potential calcd. using our e-DFT protocol. We use this framework to develop robust wavefunction embedding methods. This allows for wavefunction calcns. to be used in regions of large systems where DFT is known to perform poorly, such as van der Waals interactions and strongly correlated electrons. We discuss d. partitioning strategies for e-DFT and the accuracy of this multilevel method.