Ab initio Monte Carlo simulated annealing study of HCl(H2O)n (n=3, 4) clusters
Ab initio Monte Carlo simulated annealing study of HCl(H2O)n (n=3, 4) clusters
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DOI：
10.1021/jp9843003
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发表时间：
1999-06-17
影响因子：
2.9
通讯作者：
Ishikawa, Y
中科院分区：
文献类型：
--
作者：
Bacelo, DE;Binning, RC;Ishikawa, Y
采用从头算蒙特卡罗模拟退火（MCSA）方法研究了HCl (H2O)(n) （n = 3,4）簇的低洼结构，该方法可以有效地在势能表面上采样最小值。在蒙特卡罗模拟退火过程中，采用B3-LYP密度泛函方法，以6-31G*基集从头计算蒙特卡罗每一步的能量。每个簇中发现的所有异构体的几何形状都经过了完全的常规几何优化，并在B3-LYP和MP2水平上以6-311+G**基集进行了频率分析。在MP2优化几何形状下进行单点QCISD(T)计算，测试了B3-LYP和MP2能量排序的稳定性。HCl(H2O)(3)仅发现有强H-Cl相互作用的同分异构体。然而，发现了HCl(H2O)(4)的缔合和解离HCl结构。
Low-lying structures of HCl (H2O)(n) (n = 3, 4) clusters have been studied by ab initio Monte Carlo simulated annealing (MCSA), a procedure which efficiently samples minima on a potential energy surface. In the Monte Carlo simulated annealing procedure, energies were computed ab initio at each Monte Carlo step by the B3-LYP density functional method with 6-31G* basis sets. All geometries of the isomers found for each cluster were refined in full conventional geometry optimizations, and frequency analyses were performed at both the B3-LYP and MP2 levels with 6-311+G** basis sets. The stability of the B3-LYP and MP2 energy orderings was tested in single point QCISD(T) calculations performed at the MP2 optimized geometries. Only isomers with strong H-Cl interaction were found for HCl(H2O)(3). However, both associated- and dissociated-HCl structures of HCl(H2O)(4) were found.