Liu Chengwen, Qi Rui, Wang Qiantao, Piquemal J-P, Ren Pengyu
Department of Biomedical Engineering, The University of Texas at Austin , Austin, Texas 78712, United States.
Key Laboratory of Drug Targeting and Drug Delivery System of Education Ministry, West China School of Pharmacy, Sichuan University , Chengdu, Sichuan 610041, China.
J Chem Theory Comput. 2017 Jun 13;13(6):2751-2761. doi: 10.1021/acs.jctc.7b00225. Epub 2017 May 12.
The nonadditive many-body interactions are significant for structural and thermodynamic properties of condensed phase systems. In this work we examined the many-body interaction energy of a large number of common organic/biochemical molecular clusters, which consist of 18 chemical species and cover nine common organic elements, using the Møller-Plesset perturbation theory to the second order (MP2) [ Møller et al. Phys. Rev. 1934 , 46 , 618 . ]. We evaluated the capability of Thole-based dipole induction models to capture the many-body interaction energy. Three models were compared: the original model and parameters used by the AMOEBA force field, a variation of this original model where the damping parameters have been reoptimized to MP2 data, and a third model where the damping function form applied to the permanent electric field is modified. Overall, we find the simple classical atomic dipole models are able to capture the 3- and 4-body interaction energy across a wide variety of organic molecules in various intermolecular configurations. With modified Thole models, it is possible to further improve the agreement with MP2 results. These models were also tested on systems containing metal/halogen ions to examine the accuracy and transferability. This work suggests that the form of damping function applied to the permanent electrostatic field strongly affects the distance dependence of polarization energy at short intermolecular separations.
非加和多体相互作用对凝聚相体系的结构和热力学性质具有重要意义。在本工作中，我们使用二阶Møller-Plesset微扰理论（MP2）[Møller等人，《物理评论》，1934年，第46卷，第618页]，研究了大量常见有机/生化分子簇的多体相互作用能，这些分子簇由18种化学物质组成，涵盖9种常见有机元素。我们评估了基于Thole的偶极诱导模型捕捉多体相互作用能的能力。比较了三种模型：原始模型及AMOEBA力场使用的参数、对原始模型进行修改后将阻尼参数重新优化至MP2数据的变体模型，以及对应用于永久电场的阻尼函数形式进行修改的第三种模型。总体而言，我们发现简单的经典原子偶极模型能够在各种分子间构型下捕捉多种有机分子的三体和四体相互作用能。通过修改后的Thole模型，有可能进一步提高与MP2结果的一致性。这些模型还在含有金属/卤素离子的体系上进行了测试，以检验其准确性和可转移性。本工作表明，应用于永久静电场的阻尼函数形式在短分子间距离时强烈影响极化能的距离依赖性。
