Hartree—Fock solutions as a quasidiabatic basis for nonorthogonalconfiguration interaction

摘要

Using the method of self-consistent field metadynamics, we locate some of the low-energy solutionsto the Hartree–Fock (HF) equations on LiF and 03. The located solutions qualitatively resemble theadiabatic electronic states in these systems. We formulate the method of nonorthogonalConfiguration Interaction (CI) to interact these solutions with cubic scaling with system size andquadratic scaling with the number of solutions. The resultant solutions display the avoided crossingsand, in O_3, a conical intersection expected of the adiabatic states. In LiF the relevant solutionscoalesce and disappear from Unrestricted HF space indicating a more general HF theory isrequired.