In molecular modeling the description of the interactions between molecules forms the basis for a correct prediction of macroscopic observables. Here, we derive atomic charges from the implicitly polarized electron density of 11 molecules in the SAMPL6 challenge using the Hirshfeld-I and Minimal Basis Set Iterative Stockholder (MBIS) partitioning method. These atomic charges combined with other parameters in the GAFF force field and different water/octanol models were then used in alchemical free energy calculations to obtain hydration and solvation free energies, which after correction for the polarization cost, result in the blind prediction of the partition coefficient. From the tested partitioning methods and water models the S-MBIS atomic charges with the TIP3P water model presented the smallest deviation from the experiment. Conformational dependence of the free energies and the energetic cost associated with the polarization of the electron density are discussed.

中文翻译：

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SAMPL6辛醇-水分配系数，来自具有MBIS原子电荷的炼金术自由能计算。

在分子建模中，对分子之间相互作用的描述构成了正确预测宏观可观察物的基础。在这里，我们使用Hirshfeld-I和最小基础集迭代股票持有人（MBIS）分配方法从SAMPL6挑战中11个分子的隐式极化电子密度中得出原子电荷。然后将这些原子电荷与GAFF力场中的其他参数以及不同的水/辛醇模型结合起来，用于炼金术自由能计算中，获得水合和溶剂化自由能，在校正了极化成本之后，导致了对分配的盲目预测系数。从测试的分配方法和水模型中，带有TIP3P水模型的S-MBIS原子电荷与实验的偏差最小。