标题： 两种混合范德华密度泛函在分子共价和非共价结合中的评估 显示英文标题

标题： Assessment of two hybrid van der Waals density functionals for covalent and non-covalent binding of molecules

摘要： 使用25%的Fock交换构建了两种混合范德华密度泛函（vdW-DF），分别与i）一致交换的vdW-DF-cx泛函和ii）vdW-DF2泛函结合。评估了描述分子共价和非共价结合特性的能力。对于与共价结合相关的性质，原子化能（G2-1集）、分子反应能（G2RC集）以及电离能（G21IP集）与实验参考值进行了基准测试。我们发现混合vdW-DF-cx的结果与标准无经验混合PBE0 [JCP 110, 6158 (1996)]的结果相当相似。混合vdW-DF2表现出略有不同的趋势，平均而言与参考能量有显著偏差，G2-1集的平均绝对偏差为14.5千卡/摩尔。使用基于波函数的量子化学结果作为参考，通过非共价键合二聚体的S22基准集和小卤代分子二聚体的X40集评估了分子的非共价结合特性。对于S22集，混合vdW-DF-cx在主要氢键系统中表现优于标准vdW-DF-cx。混合vdW-DF2相对于标准vdW-DF2略有改进。在X40集上也发现了类似趋势，混合vdW-DF-cx在涉及强极性氢卤酸的结合中表现特别好，但在结合能很小的系统中表现较差。我们对X40集的研究表明，将Fock交换与vdW-DF混合具有潜力，但也突显了此处构建的混合泛函的不足之处。混合vdW-DF-cx在共价键系统中的良好表现，以及在非共价键系统中揭示的优势和问题，使本研究成为开发更精确混合vdW-DF的良好起点。 显示英文摘要

摘要： Two hybrid van der Waals density functionals (vdW-DFs) are constructed using 25%, Fock exchange with i) the consistent-exchange vdW-DF-cx functional and ii) with the vdW-DF2 functional. The ability to describe covalent and non-covalent binding properties of molecules are assessed. For properties related to covalent binding, atomization energies (G2-1 set), molecular reaction energies (G2RC set), as well as ionization energies (G21IP set) are benchmarked against experimental reference values. We find that hybrid-vdW-DF-cx yields results that are rather similar to those of the standard non-empirical hybrid PBE0 [JCP 110, 6158 (1996)]. Hybrid vdW-DF2 follows somewhat different trends, showing on average significantly larger deviations from the reference energies, with a MAD of 14.5 kcal/mol for the G2-1 set. Non-covalent binding properties of molecules are assessed using the S22 benchmark set of non-covalently bonded dimers and the X40 set of dimers of small halogenated molecules, using wavefunction-based quantum chemistry results for references. For the S22 set, hybrid-vdW-DF-cx performs better than standard vdW-DF-cx for the mostly hydrogen-bonded systems. Hybrid-vdW-DF2 offers a slight improvement over standard vdW-DF2. Similar trends are found for the X40 set, with hybrid-vdW-DF-cx performing particularly well for binding involving the strongly polar hydrogen halides, but poorly for systems with tiny binding energies. Our study of the X40 set reveals both the potential of mixing Fock exchange with vdW-DF, but also highlights shortcomings of the hybrids constructed here. The solid performance of hybrid-vdW-DF-cx for covalent-bonded systems, as well as the strengths and issues uncovered for non-covalently bonded systems, makes this study a good starting point for developing even more precise hybrid vdW-DFs.