Numerical study on the partitioning of the molecular polarizability into fluctuating charge and induced atomic dipole contributions.
Numerical study on the partitioning of the molecular polarizability into fluctuating charge and induced atomic dipole contributions.
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DOI：
10.1021/acs.jpca.5b03159
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发表时间：
2015-06-04
期刊：
影响因子：
--
通讯作者：
Shao Y
中科院分区：
文献类型：
--
作者：
Mei Y;Simmonett AC;Pickard FC 4th;DiStasio RA Jr;Brooks BR;Shao Y
为了进行详细的分析的分子的静态极化率，这是一个均匀的外部电场的分子的响应，分子极化率计算使用有限差分法为21个小分子，使用密度泛函理论。在常用的9种电荷布居方案（Löwdin，Mulliken，Becke，Hirshfeld，CM 5，Hirshfeld-I，NPA，CHELPG，MK-ESP）中，电荷涨落对分子极化率的贡献占主导地位，其比例从Hirshfeld或CM 5方案的59.9%到Mulliken方案的96.2%不等。利用Hirshenk-I方案计算了诱导原子偶极对分子极化率的贡献，发现8个小分子和水五聚体中的原子极化率对大多数原子都是各向异性的.总体而言，结果表明：（a）在未来的极化力场发展中，可能应该更多地强调电荷涨落项;（B）在完全或部分基于诱导原子偶极子的极化力场中，各向异性极化率可能比各向同性极化率更合适。
In order to carry out a detailed analysis of the molecular static polarizability, which is the response of the molecule to a uniform external electric field, the molecular polarizability was computed using the finite-difference method for 21 small molecules, using density functional theory. Within nine charge population schemes (Löwdin, Mulliken, Becke, Hirshfeld, CM5, Hirshfeld-I, NPA, CHELPG, MK-ESP) in common use, the charge fluctuation contribution is found to dominate the molecular polarizability, with its ratio ranging from 59.9% with the Hirshfeld or CM5 scheme to 96.2% with the Mulliken scheme. The Hirshfeld-I scheme is also used to compute the other contribution to the molecular polarizability coming from the induced atomic dipoles, and the atomic polarizabilities in 8 small molecules and water pentamer are found to be highly anisotropic for most atoms. Overall, the results suggest that (a) more emphasis probably should be placed on the charge fluctuation terms in future polarizable force field development; (b) an anisotropic polarizability might be more suitable than an isotropic one in polarizable force fields based entirely or partially on the induced atomic dipoles.