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Indexed by:期刊论文

Date of Publication:2011-10-01

Journal:THEORETICAL CHEMISTRY ACCOUNTS

Included Journals:Scopus、SCIE

Volume:130

Issue:2-3

Page Number:341-352

ISSN No.:1432-881X

Key Words:Water cluster; Density functional theory; MP2; CCSD(T); Basis set; Structures; Relative energies; Stabilization energy; Dipole moment; Vibrational frequencies

Abstract: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.