How To Arrive at Accurate Benchmark Values for Transition Metal Compounds: Computation or Experiment?
How To Arrive at Accurate Benchmark Values for Transition Metal Compounds: Computation or Experiment?
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DOI：
10.1021/acs.jctc.7b00688
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发表时间：
2017-11-01
影响因子：
5.5
通讯作者：
de Oliveira-Filho, Antonio G. S.
中科院分区：
文献类型：
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作者：
Aoto, Yuri A.;de Lima Batista, Ana Paula;de Oliveira-Filho, Antonio G. S.
为了分析哪种参考数据适合于过渡金属化合物的基准量子化学方法，我们提出了以下内容：（a）60个过渡金属双原子分子的集合，其实验推导的解离能，平衡距离，并且谐波振动频率是已知的，以及（B）基于具有基组外推的耦合簇理论的复合计算方法，包括核心价相关性，相对论和多参考效应的修正。后者的修正是从内部收缩多参考耦合团簇（icMRCC）理论。这种复合方法已被用来获得的解离能和光谱常数为60分子在我们的数据集。根据以前对一个分子子集的研究，我们发现，在许多情况下，多参考校正是相当小的，CCSD（T）可以提供准确的参考值，如果完整的基组极限探索。此外，在CCSD（T）不是一个很好的近似的情况下，多参考校正改善了结果。然而，在少数情况下，与实验的强烈偏差仍然存在，这不能用计算方法中的剩余误差来解释。我们认为，这些实验得出的值需要仔细修订。这也表明，基准近似计算方法的可靠参考值并不总是容易通过实验和准确的计算提供了一种替代方法来访问它们。为了评估参考数据的选择如何影响基准研究，我们针对实验和计算的参考值测试了本数据集中分子的10个DFT泛函。尽管这两组参考值之间的差异，我们发现，DFT泛函的相对性能的排名几乎是独立的选择的参考。
With the objective of analyzing which kind of reference data is appropriate for benchmarking quantum chemical approaches for transition metal compounds, we present the following, (a) a collection of 60 transition metal diatomic molecules for which experimentally derived dissociation energies, equilibrium distances, and harmonic vibrational frequencies are known and (b) a composite computational approach based on coupled-cluster theory with basis set extrapolation, inclusion of core-valence correlation, and corrections for relativistic and multireference effects. The latter correction was obtained from internally contracted multi reference coupled-cluster (icMRCC) theory. This composite approach has been used to obtain the dissociation energies and spectroscopic constants for the 60 molecules in our data set. In accordance with previous studies on a subset of molecules, we find that multireference corrections are rather small in many cases and CCSD(T) can provide accurate reference values, if the complete basis set limit is explored. In addition, the multireference correction improves the results in cases where CCSD(T) is not a good approximation. For a few cases, however, strong deviations from experiment persist, which cannot be explained by the remaining error in the computational approach. We suggest that these experimentally derived values require careful revision. This also shows that reliable reference values for benchmarking approximate computational methods are not always easily accessible via experiment and accurate computations may provide an alternative way to access them. In order to assess how the choice of reference data affects benchmark studies, we tested 10 DFT functionals for the molecules in the present data set against experimental and calculated reference values. Despite the differences between these two sets of reference values, we found that the ranking of the relative performance of the DFT functionals is nearly independent of the chosen reference.