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Vibrational computations beyond the harmonic approximation: Performances of the B3LYP density functional for semirigid molecules
Author(s) -
Carbonniere Philippe,
Lucca Tecla,
Pouchan Claude,
Rega Nadia,
Barone Vincenzo
Publication year - 2005
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.20170
Subject(s) - anharmonicity , basis set , computation , set (abstract data type) , harmonic , basis (linear algebra) , density functional theory , quality (philosophy) , computational chemistry , mathematics , molecule , chemistry , physics , statistical physics , algorithm , computer science , quantum mechanics , geometry , programming language
The performances of the B3LYP density functional in the computation of harmonic and anharmonic frequencies were tested using 14 standard basis sets of double and triple zeta quality for a set of semirigid molecules containing from 4 to 12 atoms. The quality of the results is assessed by comparison with the most reliable computations available in the literature. The study reveals that the relatively cheap 6‐31+G(d,p) basis set performs a very good job for harmonic frequency calculations and that B3LYP anharmonicities are in close agreement with the reference values irrespective of the basis set used. On these grounds “hybrid force fields” are proposed to achieve the best compromise between computer time and quality of the results. © 2005 Wiley Periodicals, Inc. J Comput Chem 26: 384–388, 2005