What is the best density functional to describe water clusters: evaluation of widely used density functionals with various basis sets for (H2O)n (n聽=聽1鈥?0)
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- 作者：Fengyu Li (13)
Lu Wang (1)
Jijun Zhao (1) zhaojj@dlut.edu.cn
John Rui-Hua Xie (2)
Kevin E. Riley (45)
Zhongfang Chen (5) zhongfangchen@gmail.com - 关键词：Water cluster – ; Density functional theory – ; MP2 – ; CCSD(T) – ; Basis set – ; Structures – ; Relative energies – ; Stabilization energy – ; Dipole moment – ; Vibrational frequencies
- 刊名：Theoretical Chemistry Accounts ; Theory ; Computation ; and Modeling (Theoretica Chimica Acta)
- 出版时间：October 2011
- 出版年：2011
- 期刊代码：108_1432-881X
- 类别：ph
- 卷：130
- 期：2-3
- 页码：341-352
- 数据来源：sp
摘要
The geometric structures, stabilization energies, dipole moments, and vibrational frequencies of the neutral water clusters (H2O) n , with n = 1–10, were investigated using density functional theory along with a variety of exchange-correlation functionals (LDA with SVWN5 parameterization, GGA with BLYP, PW91, PBE, B3LYP, X3LYP, PBE0, PBE1W, M05-2X, M06-2X and M06-L parameterizations) as well as high-level ab initio MP2 and CCSD(T) methods. Using the MP2 and CCSD(T) results as benchmarks, the effects of exchange-correlation functionals and basis sets were carefully examined. Each functional has its advantage in certain aspects; for example, M05-2X and X3LYP yield better geometries, and the capability of these two functionals to distinguish the relative energies between isomers are more similar to MP2. The size of the split-valence basis set (6-31G or larger), diffuse functions on the oxygen atom, and d(p) polarization on the oxygen (hydrogen) atom are crucial for an accurate description of intermolecular interaction in water clusters. The 6-31+G(2d,p) basis set is thus recommended as a compromise between computational efficiency and accuracy for structural description. We further demonstrated that the numerical basis set, TNP, performs satisfactorily in describing structural parameters of water clusters.