Ab initio calculations on halogen-bonded complexes and comparison with density functional methods.
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.
Lu
Yun-Xiang
YX
Ningbo Institute of Technology, Zhejiang University, Ningbo, 315100, China.
Zou
Jian-Wei
JW
Fan
Ji-Cai
JC
Zhao
Wen-Na
WN
Jiang
Yong-Jun
YJ
Yu
Qing-Sen
QS
D000641:Ammonia / Q000737:chemistry*; D005557:Formaldehyde / Q000737:chemistry*; D006846:Hydrocarbons, Halogenated / Q000737:chemistry*; D008956:Models, Chemical; D008958:Models, Molecular; D011789:Quantum Theory; D013816:Thermodynamics; D014867:Water / Q000737:chemistry*
D006846:Hydrocarbons, Halogenated; D014867:Water; D005557:Formaldehyde; D000641:Ammonia