Gkionis Konstantinos, Hill J Grant, Oldfield Steven P, Platts James A
School of Chemistry, Cardiff University, Park Place, Cardiff, CF10 3AT, UK.
J Mol Model. 2009 Sep;15(9):1051-60. doi: 10.1007/s00894-009-0459-4. Epub 2009 Feb 11.
The performance of Becke's half-and-half functional, BHandH, for description of non-covalent interactions is reported, using high-level ab initio results as benchmarks. Binding energies are found to be well reproduced for complexes that are bound predominantly by dispersion, whereas significant and consistent overestimation is observed for hydrogen bonded complexes. Overall, the mean average error is around 2 kcal mol(-1), for all basis sets considered. The effect of changing the proportion of exact and Slater exchange in the functional is shown to alter the balance of description of hydrogen bonded and dispersion bound complexes, but does not improve the overall performance. However, a simple multiplicative scaling of binding energies is possible, and reduces the mean average error to less than 1 kcal mol(-1). The performance of the BHandH functional for geometry optimization was also studied, and in almost all cases the difference from ab initio geometries is small, with root mean square deviations of between 0.05 and 0.20 A. Harmonic frequency calculation allow us to check whether optimized geometries are true minima at this level, and to estimate the zero point vibrational energy change on binding.
本文报道了以高水平从头算结果为基准，Becke的半经验泛函BHandH用于描述非共价相互作用的性能。对于主要由色散作用结合的复合物，发现其结合能能够得到很好的重现，而对于氢键复合物，则观察到显著且一致的高估。总体而言，对于所考虑的所有基组，平均平均误差约为2 kcal mol⁻¹。结果表明，改变泛函中精确交换和斯莱特交换的比例会改变对氢键复合物和色散结合复合物描述的平衡，但并不能提高整体性能。然而，可以对结合能进行简单的乘法缩放，将平均平均误差降低至小于1 kcal mol⁻¹。还研究了BHandH泛函用于几何优化的性能，几乎在所有情况下，与从头算几何结构的差异都很小，均方根偏差在0.05至0.20 Å之间。谐波频率计算使我们能够检查优化后的几何结构在该水平上是否为真正的极小值，并估计结合时零点振动能量的变化。
