Leverentz Hannah R, Truhlar Donald G
Department of Chemistry and Supercomputing Institute, University of Minnesota, Minneapolis, Minnesota 55455-0431, USA.
J Phys Chem A. 2008 Jul 3;112(26):6009-16. doi: 10.1021/jp8018364. Epub 2008 Jun 10.
Noncovalent interactions of a hydrogen bond donor with an aromatic pi system present a challenge for density functional theory, and most density functionals do not perform well for this kind of interaction. Here we test seven recent density functionals from our research group, along with the popular B3LYP functional, for the dimer of H 2S with benzene. The functionals considered include the four new meta and hybrid meta density functionals of the M06 suite, three slightly older hybrid meta functionals, and the B3LYP hybrid functional, and they were tested for their abilities to predict the dissociation energies of three conformations of the H 2S-benzene dimer and to reproduce the key geometric parameters of the equilibrium conformation of this dimer. All of the functionals tested except B3LYP correctly predict which of the three conformations of the dimer is the most stable. The functionals that are best able to reproduce the geometry of the equilibrium conformation of the dimer with a polarized triple-zeta basis set are M06-L, PWB6K, and MPWB1K, each having a mean unsigned relative error across the two experimentally verifiable geometric parameters of only 8%. The success of M06-L is very encouraging because it is a local functional, which reduces the cost for large simulations. The M05-2X functional yields the most accurate binding energy of a conformation of the dimer for which a binding energy calculated at the CCSD(T) level of theory is available; M05-2X gives a binding energy for the system with a difference of merely 0.02 kcal/mol from that obtained by the CCSD(T) calculation. The M06 functional performs well in both categories by yielding a good representation of the geometry of the equilibrium structure and by giving a binding energy that is only 0.19 kcal/mol different from that calculated by CCSD(T). We conclude that the new generation of density functionals should be useful for a variety of problems in biochemistry and materials where aromatic functional groups can serve as hydrogen bond acceptors.
氢键供体与芳香π体系之间的非共价相互作用对密度泛函理论提出了挑战，大多数密度泛函在处理这种相互作用时表现不佳。在此，我们测试了来自我们研究小组的七种近期密度泛函以及广受欢迎的B3LYP泛函，用于研究H₂S与苯的二聚体。所考虑的泛函包括M06系列的四种新的meta和杂化meta密度泛函、三种稍早的杂化meta泛函以及B3LYP杂化泛函，并测试了它们预测H₂S - 苯二聚体三种构象的解离能以及重现该二聚体平衡构象关键几何参数的能力。除B3LYP外，所有测试的泛函都能正确预测二聚体三种构象中哪一种最稳定。在使用极化三重ζ基组时，最能重现二聚体平衡构象几何结构的泛函是M06 - L、PWB6K和MPWB1K，它们在两个可通过实验验证的几何参数上的平均无符号相对误差仅为8%。M06 - L的成功非常令人鼓舞，因为它是一种局域泛函，这降低了大型模拟的成本。对于二聚体的一种构象，M05 - 2X泛函给出了最准确的结合能，在该构象下，理论上在CCSD(T)水平计算得到的结合能是可用的；M05 - 2X给出的该体系结合能与CCSD(T)计算得到的结果仅相差0.02 kcal/mol。M06泛函在这两个方面都表现良好，它能很好地表示平衡结构的几何形状，其给出的结合能与CCSD(T)计算得到的结果仅相差0.19 kcal/mol。我们得出结论，新一代密度泛函对于生物化学和材料领域中各种涉及芳香官能团可作为氢键受体的问题应该是有用的。
