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Dispersion treatment for NDDO‐based semiempirical MO techniques
Author(s) -
Martin Bodo,
Clark Timothy
Publication year - 2005
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.20856
Subject(s) - polarizability , mndo , dispersion (optics) , casimir effect , chemistry , series (stratigraphy) , atomic orbital , quantum mechanics , computational chemistry , molecular physics , atomic physics , physics , molecule , electron , paleontology , biology
We introduce an additional term to treat dispersion in NDDO‐based semiempirical molecular orbital techniques. The dispersion energy is calculated using additive “atomic orbital” polarizability tensors determined with our modified version of Rivail's variational technique. Frequency‐dependent polarizabilities can be obtained using Padé approximants, which proved more reliable than the Unsöld approximation or a Taylor‐series approach. Dispersion energies are best calculated using the Slater–Kirkwood modification of the London formula, although they can also be obtained using the Casimir–Polder approach with frequency‐dependent polarizabilities. A test parameterization using MNDO as the semiempirical technique indicated that weak interactions can be reproduced satisfactorily. © 2005 Wiley Periodicals, Inc. Int J Quantum Chem, 2006