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Improved efficiency of focal point conformational analysis with truncated correlation consistent basis sets
Author(s) -
Kahn Kalju,
Kahn Iiris
Publication year - 2007
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.20848
Subject(s) - extrapolation , chemistry , basis set , computational chemistry , conformational isomerism , ab initio , molecule , basis (linear algebra) , ab initio quantum chemistry methods , thermodynamics , physics , mathematics , density functional theory , organic chemistry , mathematical analysis , geometry
It has been suggested that the computational cost of correlated ab initio calculations could be reduced efficiently by using truncated basis sets on hydrogen atoms (Mintz et al., J Chem Phys 2004, 121, 5629). We now explore this proposal in the context of conformational analysis of small molecules, such as hydrogen peroxide, dimethyl ether, ethyl methyl ether, formic acid, methyl formate, and several small alcohols. It is found that truncated correlation consistent basis sets that lack certain higher angular momentum functions on hydrogen atoms offer accuracy similar to traditional Dunning's basis sets for conformational analysis. Combination of such basis sets with the basis set extrapolation technique to estimate Hartree–Fock and Møller–Plesset second order energies provides composite extrapolation model chemistries that are significantly more accurate and faster than analogous single point calculations with traditional correlation consistent basis sets. Root mean square errors of best composite extrapolation model chemistries on the used set of molecules are within 0.03 kcal/mol of traditional focal point conformational energies. The applicability of composite extrapolation methods is illustrated by performing conformational analysis of tert ‐butanol and cyclohexanol. For comparison, conformational energies calculated with popular molecular mechanics force fields are also given. © 2007 Wiley Periodicals, Inc. J Comput Chem 2008