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Calculation of molecular vibrations: Selective scaling factors for semiempirical force constants
Author(s) -
Grunenberg J.,
Herges R.
Publication year - 1997
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/(sici)1096-987x(199712)18:16<2050::aid-jcc9>3.0.co;2-k
Subject(s) - force constant , cartesian coordinate system , chemistry , density functional theory , computational chemistry , scaling , bond length , normal coordinates , transformation (genetics) , molecule , mathematics , geometry , biochemistry , organic chemistry , gene
The complete force constant matrices of a set of 50 aliphatic and aromatic hydrocarbons are calculated at the density functional theory B3LYP/6–31+G( d , p ) and semiempirical PM3 levels of theory. After transformation from Cartesian to nonredundant internal coordinates, the errors in the semiempirical force constants are systematically analyzed. The force constants of the C(SINGLE BOND)C stretching coordinates can be easily corrected by a second‐order fit. Thus, only two parameters are needed to reduce the mean error from 21.2 to 1.23%. The errors of other internal coordinates, particulary those including torsional modes, exhibit a larger diversity. The performance of the correction scheme in predicting vibrational spectra is shown for several examples including buckminsterfullerene (C 60 ). © 1997 John Wiley & Sons, Inc. J Comput Chem 18 : 2050–2059, 1997