Department of Chemistry and Supercomputing Institute, University of Minnesota, 207 Pleasant Street S.E., Minneapolis, Minnesota 55455-0431, United States.
J Chem Theory Comput. 2012 Feb 14;8(2):527-41. doi: 10.1021/ct200866d. Epub 2012 Feb 3.
We propose a novel approach to deriving partial atomic charges from population analysis. The new model, called Charge Model 5 (CM5), yields class IV partial atomic charges by mapping from those obtained by Hirshfeld population analysis of density functional electronic charge distributions. The CM5 model utilizes a single set of parameters derived by fitting to reference values of the gas-phase dipole moments of 614 molecular structures. An additional test set (not included in the CM5 parametrization) contained 107 singly charged ions with nonzero dipole moments, calculated from the accurate electronic charge density, with respect to the center of nuclear charges. The CM5 model is applicable to any charged or uncharged molecule composed of any element of the periodic table in the gas phase or in solution. The CM5 model predicts dipole moments for the tested molecules that are more accurate on average than those from the original Hirshfeld method or from many other popular schemes including atomic polar tensor and Löwdin, Mulliken, and natural population analyses. In addition, the CM5 charge model is essentially independent of a basis set. It can be used with larger basis sets, and thereby this model significantly improves on our previous charge models CMx (x = 1-4 or 4M) and other methods that are prone to basis set sensitivity. CM5 partial atomic charges are less conformationally dependent than those derived from electrostatic potentials. The CM5 model does not suffer from ill conditioning for buried atoms in larger molecules, as electrostatic fitting schemes sometimes do. The CM5 model can be used with any level of electronic structure theory (Hartree-Fock, post-Hartree-Fock, and other wave function correlated methods or density functional theory) as long as an accurate electronic charge distribution and a Hirshfeld analysis can be computed for that level of theory.
我们提出了一种从密度泛函电子电荷分布的希夫尔德（Hirshfeld）Population 分析中获取部分原子电荷的新方法。新模型称为电荷模型 5（CM5），通过映射从密度泛函电子电荷分布的希夫尔德 Population 分析中获得的部分原子电荷来生成 IV 类部分原子电荷。CM5 模型利用通过拟合至 614 个分子结构的气相偶极矩参考值得到的单个参数集。附加测试集（未包含在 CM5 参数化中）包含 107 个具有非零偶极矩的单电荷离子，这些离子是根据准确的核电荷中心的电子电荷密度计算得到的。CM5 模型适用于任何元素周期表中的任何带电荷或不带电荷的分子，无论是在气相中还是在溶液中。CM5 模型预测的测试分子的偶极矩比原始希夫尔德方法或许多其他流行方案（包括原子极性张量和 Löwdin、Mulliken 和自然 Population 分析）的预测更准确。此外，CM5 电荷模型本质上与基组无关。它可以与更大的基组一起使用，因此该模型显著改进了我们之前的电荷模型 CMx（x = 1-4 或 4M）和其他容易受到基组敏感性影响的方法。CM5 部分原子电荷比从静电势得出的原子电荷的构象依赖性更小。CM5 模型不会像静电拟合方案有时那样，在较大分子的埋置原子中出现病态。CM5 模型可用于任何电子结构理论（Hartree-Fock、后 Hartree-Fock 和其他波函数相关方法或密度泛函理论），只要可以为该理论水平计算准确的电子电荷分布和希夫尔德分析。
