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New accurate benchmark energies for large water clusters: DFT is better than expected
Author(s) -
Anacker Tony,
Friedrich Joachim
Publication year - 2014
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.23539
Subject(s) - dodecahedron , basis set , benchmark (surveying) , coupled cluster , chemistry , valence (chemistry) , ab initio , density functional theory , atomic physics , physics , computational chemistry , molecule , crystallography , geography , geodesy , organic chemistry
In this work, we use MP2 and coupled‐cluster with single, double, and perturbative triple excitations [CCSD(T)] as well as their corresponding explicitly correlated (F12) counterparts to compute the interaction energies of water icosamers. The incremental scheme is used to compute benchmark energies at the CCSD(T)/CBS(45) and CCSD(T)(F12*)/cc‐pVQZ‐F12 level of theory. The four structures, dodecahedron, edge sharing, face sharing, and fused cubes, are part of the WATER27 test set and therefore, highly accurate interaction energies are required. All methods applied in this work lead to new benchmark energies for these four systems. To obtain these values, we carefully analyze the convergence of the interaction energies with respect to the basis set. Furthermore, we investigate the influence of the basis set superposition error and the core‐valence correlation. The interaction energies are: dodecahedron −198.6 kcal/mol, edge sharing −209.7 kcal/mol, face sharing −208.0 kcal/mol, and fused cubes −208.0 kcal/mol. For water clusters, we recommend to use the PW6B95 density functional of Truhlar in combination with Grimme's dispersion correction (D3), as the mean absolute error is 0.9 and the root mean‐squared deviation is only 1.4 kcal/mol. © 2014 Wiley Periodicals, Inc.