Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany.
J Chem Phys. 2017 Jul 21;147(3):034112. doi: 10.1063/1.4993215.
A new model, termed D4, for the efficient computation of molecular dipole-dipole dispersion coefficients is presented. As in the related, well established D3 scheme, these are obtained as a sum of atom-in-molecule dispersion coefficients over atom pairs. Both models make use of dynamic polarizabilities obtained from first-principles time-dependent density functional theory calculations for atoms in different chemical environments employing fractional atomic coordination numbers for interpolation. Different from the D3 model, the coefficients are obtained on-the-fly by numerical Casimir-Polder integration of the dynamic, atomic polarizabilities α(iω). Most importantly, electronic density information is now incorporated via atomic partial charges computed at a semi-empirical quantum mechanical tight-binding level, which is used to scale the polarizabilities. Extended statistical measures show that errors for dispersion coefficients with the proposed D4 method are significantly lower than with D3 and other, computationally more involved schemes. Alongside, accurate isotropic charge and hybridization dependent, atom-in-molecule static polarizabilities are obtained with an unprecedented efficiency. Damping function parameters are provided for three standard density functionals, i.e., TPSS, PBE0, and B3LYP, allowing evaluation of the new DFT-D4 model for common non-covalent interaction energy benchmark sets.
本文提出了一种新的模型 D4，用于高效计算分子偶极-偶极色散系数。与相关的、成熟的 D3 方案一样，这些系数是通过原子对之间的分子内色散系数求和得到的。这两个模型都利用了第一性原理含时密度泛函理论计算得到的原子在不同化学环境中的动态极化率，采用分数原子配位数进行插值。与 D3 模型不同的是，系数是通过对动态原子极化率α(iω)进行数值 Casimir-Polder 积分实时获得的。最重要的是，现在通过在半经验量子力学紧束缚水平上计算的原子部分电荷来纳入电子密度信息，这用于缩放极化率。扩展的统计度量表明，与 D3 模型和其他计算更复杂的方案相比，所提出的 D4 方法的色散系数误差明显更低。同时，还以空前的效率获得了准确的各向同性电荷和杂化相关的分子内静态极化率。本文还提供了三个标准密度泛函（TPSS、PBE0 和 B3LYP）的阻尼函数参数，允许评估新的 DFT-D4 模型在常见非共价相互作用能量基准集上的应用。
