Localized orbital interactions: d-electron exchange and correlation



Several approaches to treating electron correlation and exchange in localized d-orbital distributions are discussed. The approaches are designed to treat large systems such as transition metal clusters or solid surfaces by simpler approaches than configuration interaction calculations on the entire system. The analysis is based on the concept of an electronic subspace, defined by localized orbitals, embedded in a larger electronic system. An expression is developed for d-electron correlation contributions that is equivalent to an external potential. This potential can be used in conjunction with single-determinant or configuration interaction wave functions. The concept of using potentials instead of orbital basis functions to treat exchange in delocalized electronic systems is discussed. © 2003 Wiley Periodicals, Inc. Int J Quantum Chem, 2003