2-body:Many-body QM:QM study of structures, energetics, and vibrational frequencies for microhydrated halide ions
2-body:Many-body QM:QM study of structures, energetics, and vibrational frequencies for microhydrated halide ions
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DOI：
10.1080/00268976.2018.1554827
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发表时间：
2018-12
影响因子：
1.7
通讯作者：
T. Sexton;Gregory S. Tschumper
中科院分区：
文献类型：
--
作者：
T. Sexton;Gregory S. Tschumper
摘要 使用 MP2 和 CCSD(T) 量子力学 (QM) 电子结构技术以及 2 体:多体 QM:QM 方法 (2b:Mb CCSD(T):MP2) 探讨了微水合卤化物离子的优化结构、电子解离能和简谐振动频率，其中 1 体和 2 体相互作用在 CCSD(T) 理论水平上计算，同时所有高阶贡献是在 MP2 理论水平上捕获的。一般来说，之前针对中性、均质 HF 和 H2O 团簇所展示的 2b:Mb 方法的准确性和效率可扩展到这些带负电的异质系统。结果表明，MP2 方法很难为水合氟化物团簇的振动频率提供可靠的描述，尽管它对于其他水合卤化物（氯化物、溴化物和碘化物）表现良好。因此，氟化物团簇的 2b:Mb CCSD(T):MP2 方法的准确性比其他卤化物差，并且 MP2 不是推荐的低水平方法，用于使用 2b:Mb 方法或相关 QM:QM 方法对水合氟化物复合物进行高精度频率分析。图解摘要
ABSTRACT The optimised structures, electronic dissociation energies and harmonic vibrational frequencies of microhydrated halide ions have been probed with the MP2 and CCSD(T) quantum mechanical (QM) electronic structure techniques as well as with the 2-body:Many-body QM:QM method (2b:Mb CCSD(T):MP2) in which the 1- and 2-body interactions are computed at the CCSD(T) level of theory while all higher-order contributions are captured at the MP2 level of theory. In general, the accuracy and efficiency of the 2b:Mb approach previously demonstrated for neutral, homogeneous HF and HO clusters extends to these negatively charged heterogeneous systems. Results indicate the MP2 method struggles to provide a reliable description of the vibrational frequencies for hydrated fluoride clusters even though it performs well for the other hydrated halides (chloride, bromide and iodide). Consequently, the accuracy of the 2b:Mb CCSD(T):MP2 approach for fluoride clusters is poorer than the other halides, and MP2 is not a recommended low-level method for high-accuracy frequency analyses of hydrated fluoride complexes with the 2b:Mb method or related QM:QM approaches. GRAPHICAL ABSTRACT