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Comparison of some representative density functional theory and wave function theory methods for the studies of amino acids
Author(s) -
Yu Wenbo,
Liang Lei,
Lin Zijing,
Ling Sanliang,
Haranczyk Maciej,
Gutowski Maciej
Publication year - 2009
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.21091
Subject(s) - basis set , density functional theory , chemistry , conformational isomerism , computational chemistry , intramolecular force , deprotonation , protonation , hydrogen bond , wave function , hybrid functional , basis (linear algebra) , molecule , coupled cluster , atomic physics , mathematics , stereochemistry , physics , geometry , ion , organic chemistry
Energies of different conformers of 22 amino acid molecules and their protonated and deprotonated species were calculated by some density functional theory (DFT; SVWN, B3LYP, B3PW91, MPWB1K, BHandHLYP) and wave function theory (WFT; HF, MP2) methods with the 6‐311++G(d,p) basis set to obtain the relative conformer energies, vertical electron detachment energies, deprotonation energies, and proton affinities. Taking the CCSD/6‐311++G(d,p) results as the references, the performances of the tested DFT and WFT methods for amino acids with various intramolecular hydrogen bonds were determined. The BHandHLYP method was the best overall performer among the tested DFT methods, and its accuracy was even better than that of the more expensive MP2 method. The computational dependencies of the five DFT methods and the HF and MP2 methods on the basis sets were further examined with the 6‐31G(d,p), 6‐311++G(d,p), aug‐cc‐pVDZ, 6‐311++G(2df,p), and aug‐cc‐pVTZ basis sets. The differences between the small and large basis set results have decreased quickly for the hybrid generalized gradient approximation (GGA) methods. The basis set convergence of the MP2 results has been, however, very slow. Considering both the cost and the accuracy, the BHandHLYP functional with the 6‐311++G(d,p) basis set is the best choice for the amino acid systems that are rich in hydrogen bonds. © 2008 Wiley Periodicals, Inc. J Comput Chem 2009