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首页> 外文期刊>The journal of physical chemistry, A. Molecules, spectroscopy, kinetics, environment, & general theory >Density Functional Theory Is More Accurate Than Coupled-Cluster Theory in the Study of the Thermochemistry of Species Containing the F-O Bond
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Density Functional Theory Is More Accurate Than Coupled-Cluster Theory in the Study of the Thermochemistry of Species Containing the F-O Bond

机译：在研究含F-O键的物质的热化学过程中，密度泛函理论比耦合簇理论更准确

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摘要

The standard singles and doubles coupled-cluster method including perturbational treatment of connected triple excitations, CCSD(T), and density functional methods, DFT, using a large, uncontracted, atomic natural orbital (ANO) basis set were employed for calculating the enthalpies of formation of some first-row atoms (H,N,O,F) as well as diatomic and triatomic molecules formed with them. Molecular enthalpies of formation at 298.15 K were obtained from enthalpies of reaction of the atoms, homonuclear diatomic molecules, and isodesmic reactions, It is shown that the errors are the minimum when isodesmic reactions are used. However, contrary to accepted belief, CCSD(T) gives a larger deviation from experiment than DFT in the latter case. DFT exhibits similar accuracy when using a very small basis set (6-31G) to that with the extended basis set, while the errors obtained with CCSD(T) are much larger. It is concluded that DFT is a more accurate and convenient computational tool than CCSD(T) for the thermochemical study of species containing the F-O bond.
机译：采用标准的单双联耦合簇方法，包括对相连的三重激发进行微扰处理（CCSD（T））和密度泛函方法DFT（使用大型，未收缩的原子自然轨道（ANO）基集）来计算形成一些第一行原子（H，N，O，F）以及与之形成的双原子和三原子分子。从原子，同核双原子分子和等渗反应的反应焓获得了在298.15 K处的形成分子焓，结果表明，当使用等渗反应时，误差最小。但是，与公认的观点相反，在后一种情况下，CCSD（T）与DFT的偏差更大。当使用非常小的基础集（6-31G）时，DFT表现出与扩展基础集相似的精度，而使用CCSD（T）获得的误差要大得多。结论是，对于包含F-O键的物质进行热化学研究，DFT比CCSD（T）是一种更准确，更方便的计算工具。

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