COMP 208 |
Conventional ab-initio electronic structure methods often fail to provide a qualitatively correct description of spin-state energetics of systems containing transition metals. The paradigmatic reaction of the oxidation of H2 by FeO+ demonstrates the severe limitations of common DFT functionals to provide a correct description of multiplet splittings. A DFT based GGA+U approach is introduced here to predict reaction energetics with greatly-improved accuracy, as compared to benchmark calculations that use high-level MP2/MP4 and coupled-cluster approaches. The value of U, a Hubbard-like correction, is obtained in a fully ab-initio fashion using linear-response theory and is thus not a free parameter. Transition states are identified using nudged-elastic band and string methods adapted to employ GGA+U. Thanks to the efficiency of plane-wave basis set implementation, inexpensive scaling of the technique to large biochemical complexes is demonstrated. |
Poster Session -- Sponsored by Novartis Institutes for BioMedical Research
6:00 PM-8:00 PM, Tuesday, 30 August 2005 Washington DC Convention Center -- Hall A, Poster
Division of Computers in Chemistry |