Calculation of smooth potential energy surfaces using local electron correlation methods
- Institut fuer Theoretische Chemie, Universitaet Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)
The geometry dependence of excitation domains in local correlation methods can lead to noncontinuous potential energy surfaces. We propose a simple domain merging procedure which eliminates this problem in many situations. The method is applied to heterolytic bond dissociations of ketene and propadienone, to SN2 reactions of Cl{sup -} with alkylchlorides, and in a quantum mechanical/molecular mechanical study of the chorismate mutase enzyme. It is demonstrated that smooth potentials are obtained in all cases. Furthermore, basis set superposition error effects are reduced in local calculations, and it is found that this leads to better basis set convergence when computing barrier heights or weak interactions. When the electronic structure strongly changes between reactants or products and the transition state, the domain merging procedure leads to a balanced description of all structures and accurate barrier heights.
- OSTI ID:
- 20864335
- Journal Information:
- Journal of Chemical Physics, Vol. 125, Issue 18; Other Information: DOI: 10.1063/1.2364487; (c) 2006 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-9606
- Country of Publication:
- United States
- Language:
- English
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