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Diffuse functions in natural bond orbital analysis
Author(s) -
Goodman Lionel,
Sauers Ronald R.
Publication year - 2006
Publication title -
journal of computational chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.907
H-Index - 188
eISSN - 1096-987X
pISSN - 0192-8651
DOI - 10.1002/jcc.20519
Subject(s) - natural bond orbital , basis set , atomic orbital , valence (chemistry) , localized molecular orbitals , chemistry , valence bond theory , molecular orbital , atomic physics , molecule , computational chemistry , molecular physics , physics , linear combination of atomic orbitals , quantum mechanics , density functional theory , electron , organic chemistry
We show that diffuse function augmentation of Pople basis sets at the 6‐311G RHF and B3LYP levels strongly impact conclusions drawn from natural bond orbital (NBO) analysis. The large spatial extent of high quantum number Rydberg orbitals introduced by augmentation contribute importantly to the valence space of neighboring atoms due to the likely inadequacy of the 311 valence functions. In contrast, lesser anomalies are found for augmentation of double zeta type 6‐31G. The energetic anomalies found for bond and antibond NBO descriptions, made nonlocal by augmentation, are most serious for molecules with four or more heavy atoms. For these cases augmentation can lead to nonphysical results. NBO results using Dunning‐type correlation consistent orbitals exhibit much weaker basis set dependence than those using the Pople basis sets.© 2006 Wiley Periodicals, Inc. J Comput Chem 2007