Mulliken Center for Theoretical Chemistry, Institut für Physikalische und Theoretische Chemie der Universität Bonn, Beringstr. 4, D-53115 Bonn, Germany.
J Chem Phys. 2017 Oct 28;147(16):161708. doi: 10.1063/1.4991798.
A black-box type procedure is presented for the generation of a molecule-specific, intermolecular potential energy function. The method uses quantum chemical (QC) information from our recently published extended tight-binding semi-empirical scheme (GFN-xTB) and can treat non-covalently bound complexes and aggregates with almost arbitrary chemical structure. The necessary QC information consists of the equilibrium structure, Mulliken atomic charges, charge centers of localized molecular orbitals, and also of frontier orbitals and orbital energies. The molecular pair potential includes model density dependent Pauli repulsion, penetration, as well as point charge electrostatics, the newly developed D4 dispersion energy model, Drude oscillators for polarization, and a charge-transfer term. Only one element-specific and about 20 global empirical parameters are needed to cover systems with nuclear charges up to radon (Z = 86). The method is tested for standard small molecule interaction energy benchmark sets where it provides accurate intermolecular energies and equilibrium distances. Examples for structures with a few hundred atoms including charged systems demonstrate the versatility of the approach. The method is implemented in a stand-alone computer code which enables rigid-body, global minimum energy searches for molecular aggregation or alignment.
提出了一种黑盒类型的方法，用于生成分子特异性的分子间势能函数。该方法使用我们最近发表的扩展紧束缚半经验方案 (GFN-xTB) 的量子化学 (QC) 信息，可以处理具有任意化学结构的非共价键复合物和聚集体。所需的 QC 信息包括平衡结构、Mulliken 原子电荷、局域分子轨道的电荷中心，以及前沿轨道和轨道能量。分子对势能包括模型密度相关的 Pauli 排斥、穿透以及点电荷静电，新开发的 D4 色散能模型、极化的 Drude 振子以及电荷转移项。只需要一个元素特定的和大约 20 个全局经验参数来覆盖核电荷数高达氡 (Z = 86) 的系统。该方法经过标准小分子相互作用能基准集的测试，提供了准确的分子间能量和平衡距离。包括带电系统在内的具有数百个原子的结构示例证明了该方法的多功能性。该方法在一个独立的计算机代码中实现，能够进行刚性体、全局最小能量搜索，以实现分子聚集或对齐。
