We present a new analysis of exchange and dispersion effects for calculating halogen-bonding interactions in a wide variety of complex dimers (69 total) within the XB18 and XB51 benchmark sets. Contrary to previous work on these systems, we find that dispersion plays a more significant role than exact exchange in accurately calculating halogen-bonding interaction energies, which are further confirmed by extensive SAPT analyses. In particular, we find that even if the amount of exact exchange is nonempirically tuned to satisfy known DFT constraints, we still observe an overall improvement in predicting dissociation energies when dispersion corrections are applied, in stark contrast to previous studies (Kozuch, S.; Martin, J. M. L. J. Chem. Theory Comput. 2013, 9, 1918−1931). In addition to these new analyses, we correct several (14) inconsistencies in the XB51 set, which is widely used in the scientific literature for developing and benchmarking various DFT methods. Together, these new analyses and revised benchmarks emphasize the importance of dispersion and provide corrected reference values that are essential for developing/parametrizing new DFT functionals, specifically for complex halogen-bonding interactions.

中文翻译：

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卤素键相互作用：修订的基准和交换与分散的新评估

我们提出了一种交换和分散效应的新分析，用于计算XB18和XB51基准范围内各种复杂二聚体（共69个）中的卤素键相互作用。与以前在这些系统上的工作相反，我们发现在精确计算卤素键相互作用能方面，色散起着比精确交换更重要的作用，广泛的SAPT分析进一步证实了这一点。特别是，我们发现即使对非精确调节的精确交换量进行了非经验性的调整以满足已知的DFT约束条件，与以前的研究形成鲜明对比的是，当应用色散校正时，我们仍然观察到预测离解能的整体改进（Kozuch，S .;马丁，JML J.化学理论COMPUT。 2013，9，1918−1931）。除了这些新的分析之外，我们还纠正了XB51集中的几处（14）不一致之处，XB51集在科学文献中广泛用于开发和基准化各种DFT方法。这些新的分析和经过修订的基准共同强调了分散的重要性，并提供了校正的参考值，这对于开发/参数化新的DFT功能至关重要，特别是对于复杂的卤素键相互作用而言。