Department of Chemistry, Pohang University of Science and Technology (POSTECH), Pohang 790-784, Korea.
J Comput Chem. 2012 Jul 30;33(20):1662-72. doi: 10.1002/jcc.22985. Epub 2012 May 8.
Recently, many polarizable force fields have been devised to describe induction effects between molecules. In popular polarizable models based on induced dipole moments, atomic polarizabilities are the essential parameters and should be derived carefully. Here, we present a parameterization scheme for atomic polarizabilities using a minimization target function containing both molecular and atomic information. The main idea is to adopt reference data only from quantum chemical calculations, to perform atomic polarizability parameterizations even when relevant experimental data are scarce as in the case of electronically excited molecules. Specifically, our scheme assigns the atomic polarizabilities of any given molecule in such a way that its molecular polarizability tensor is well reproduced. We show that our scheme successfully works for various molecules in mimicking dipole responses not only in ground states but also in valence excited states. The electrostatic potential around a molecule with an externally perturbing nearby charge also exhibits a near-quantitative agreement with the reference data from quantum chemical calculations. The limitation of the model with isotropic atoms is also discussed to examine the scope of its applicability.
最近，已经设计出了许多极化力场来描述分子之间的诱导效应。在基于诱导偶极矩的流行极化模型中，原子极化率是基本参数，应该仔细推导。在这里，我们提出了一种使用包含分子和原子信息的最小化目标函数来参数化原子极化率的方案。主要思想是仅采用量子化学计算的参考数据，即使在相关实验数据稀缺的情况下（如电子激发分子的情况），也可以进行原子极化率参数化。具体来说，我们的方案以这样的方式分配任何给定分子的原子极化率，即其分子极化率张量得到很好的再现。我们表明，我们的方案成功地用于各种分子，不仅在基态，而且在价激发态下模拟偶极响应。在外加邻近电荷的分子周围的静电势也与量子化学计算的参考数据非常吻合。还讨论了各向同性原子模型的局限性，以检验其适用性范围。
