Multiconfiguration optimized effective potential method for a density-functional treatment of static correlation.

Abstract

A density-functional framework for handling static correlation was developed through the derivation of a multiconfiguration optimized effective potential (MCOEP) method. Unlike conventional multiconfiguration self-consistent field (MCSCF) approaches and earlier hybrid MCSCF-DFT schemes, the MCOEP method produces physically well-defined orbital and eigenvalue spectra. The method accommodates both ground and excited electronic states. Implementation was carried out using the localized Hartree-Fock approximation, yielding a multiconfiguration localized Hartree-Fock formalism. Benchmark applications to hydrogen molecule dissociation, ethene isomerization, and cyclobutadiene isomerization demonstrated the method's capacity to handle systems exhibiting pronounced static correlation effects.