Molecular polarisabilities calculated with density functional theory using both the local density approximation and a gradient corrected functional are contrasted with results obtained using standard ab initio methods. The ab initio methods used are SCE second-order and fourth-order M¢ller-Plesset p
Ab initio calculations on halogen-bonded complexes and comparison with density functional methods
✍ Scribed by Yun-Xiang Lu; Jian-Wei Zou; Ji-Cai Fan; Wen-Na Zhao; Yong-Jun Jiang; Qing-Sen Yu
- Publisher
- John Wiley and Sons
- Year
- 2009
- Tongue
- English
- Weight
- 163 KB
- Volume
- 30
- Category
- Article
- ISSN
- 0192-8651
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✦ Synopsis
Abstract
A systematic theoretical investigation on a series of dimeric complexes formed between some halocarbon molecules and electron donors has been carried out by employing both ab initio and density functional methods. Full geometry optimizations are performed at the Moller–Plesset second‐order perturbation (MP2) level of theory with the Dunning's correlation‐consistent basis set, aug‐cc‐pVDZ. Binding energies are extrapolated to the complete basis set (CBS) limit by means of two most commonly used extrapolation methods and the aug‐cc‐pVXZ (X = D, T, Q) basis sets series. The coupled cluster with single, double, and noniterative triple excitations [CCSD(T)] correction term, determined as a difference between CCSD(T) and MP2 binding energies, is estimated with the aug‐cc‐pVDZ basis set. In general, the inclusion of higher‐order electron correlation effects leads to a repulsive correction with respect to those predicted at the MP2 level. The calculations described herein have shown that the CCSD(T) CBS limits yield binding energies with a range of −0.89 to −4.38 kcal/mol for the halogen‐bonded complexes under study. The performance of several density functional theory (DFT) methods has been evaluated comparing the results with those obtained from MP2 and CCSD(T). It is shown that PBEKCIS, B97‐1, and MPWLYP functionals provide accuracies close to the computationally very expensive ab initio methods. © 2008 Wiley Periodicals, Inc. J Comput Chem, 2009
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