The Journal of Physical Chemistry A · 2009 · 192 citations · 49 references
Natural SciencesChemistryPhysicsComputational ChemistryMolecular PhysicsTheoretical ChemistryAb Initio MethodsConfiguration InteractionDensity Functional TheoryEnergy MinimizationMolecular Orbital TheoryMultireference MethodsCis ApproachConical IntersectionsConstrained Density Functional TheoryMolecular Geometry OptimizationMultireference Density Functional TheoryMultistate Multireference Perturbation TheorySecond-order Perturbation TheorySpin-polarized Density Functional Theory
Conical intersections (CIs) of ethylene have been successfully determined using spin-flip density functional theory (SFDFT) combined with a penalty-constrained optimization method. We present in detail three structures, twisted-pyramidalized, hydrogen-migrated, and ethylidene CIs. In contrast to the linear response time-dependent density functional theory, which predicts a purely twisted geometry without pyramidalization as the S(1) global minimum, SFDFT gives a pyramidalized structure. Therefore, this is the first correct optimization of CI points of twisted ethylene by the DFT method. The calculated energies and geometries are in good agreement with those obtained by the multireference configuration interaction (MR-CI) method and the multistate formulation of second-order multireference perturbation theory (MS-CASPT2).
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General atomic and molecular electronic structure system
Michael W. Schmidt, Kim K. Baldridge, Jerry A. Boatz et al. · Journal of Computational Chemistry · 1993 · 20.2K citations
Natural Sciences, Chemistry, Physics +17