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Soft Coulomb hole method applied to molecules
Author(s) -
OrtegaCastro J.,
AlfonsoMéndez L.,
Otto P.,
HernándezLaguna A.
Publication year - 2006
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.21244
Subject(s) - diatomic molecule , heteronuclear molecule , coulomb , gaussian , electronic correlation , physics , molecule , hartree–fock method , atomic physics , perturbation theory (quantum mechanics) , chemistry , molecular physics , quantum mechanics , electron
The soft Coulomb hole method introduces a perturbation operator, defined by − e −ω r 12 2/ r 12 to take into account electron correlation effects, where ω represents the width of the Coulomb hole. A new parametrization for the soft Coulomb hole operator is presented with the purpose of obtaining better molecular geometries than those resulting from Hartree–Fock calculations, as well as correlation energies. The 12 parameters included in ω were determined for a reference set of 12 molecules and applied to a large set of molecules (38 homo‐ and heteronuclear diatomic molecules, and 37 small and medium‐size molecules). For these systems, the optimized geometries were compared with experimental values; correlation energies were compared with results of the MP2, B3LYP, and Gaussian 3 approach. On average, molecular geometries are better than the Hartree–Fock values, and correlation energies yield results halfway between MP2 and B3LYP. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007