Assessing many-body contributions to intermolecular interactions of the AMOEBA force field using energy decomposition analysis of electronic structure calculations
Assessing many-body contributions to intermolecular interactions of the AMOEBA force field using energy decomposition analysis of electronic structure calculations
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DOI：
10.1063/1.4999905
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发表时间：
2017-10-28
影响因子：
4.4
通讯作者：
Head-Gordon, Teresa
中科院分区：
文献类型：
--
作者：
Demerdash, Omar;Mao, Yuezhi;Head-Gordon, Teresa
在这项工作中，我们通过与基于绝对定域分子轨道的能量分解方法(ALMO-EDA)的比较，评估了经典阿米巴模型描述多体相互作用的准确性，如极化、电荷转移、Pauli排斥和色散。对于本文所研究的离子-水三聚体体系，当分析多体展开的二体和三体贡献时，发现三体对Pauli排斥和色散的贡献在Almo-EDA下是可以忽略的，从而支持了阿米巴14-7 van derWaals项中的成对加性近似的有效性。然而，与相应的Almo-EDA项相比，阿米巴显示出对电荷转移丢失效应的误差的不完全抵消以及对极化的距离依赖的不正确。我们将较大的二体和三体极化误差追溯到阿米巴中使用的Thole阻尼方案，尽管Thole阻尼中的宽度参数可以改变，以改善与Almo-EDA极化在平衡点附近的一致性，但不能再现作为分子间距离函数的正确极化轮廓。结果表明，有必要重新检查阿米巴力场中使用的阻尼和极化模型，并对可极化力场的一般公式提供进一步的见解。由AIP出版公司出版。
In this work, we evaluate the accuracy of the classical AMOEBA model for representing many-body interactions, such as polarization, charge transfer, and Pauli repulsion and dispersion, through comparison against an energy decomposition method based on absolutely localized molecular orbitals (ALMO-EDA) for the water trimer and a variety of ion-water systems. When the 2- and 3-body contributions according to the many-body expansion are analyzed for the ion-water trimer systems examined here, the 3-body contributions to Pauli repulsion and dispersion are found to be negligible under ALMO-EDA, thereby supporting the validity of the pairwise-additive approximation in AMOEBA's 14-7 van derWaals term. However AMOEBA shows imperfect cancellation of errors for the missing effects of charge transfer and incorrectness in the distance dependence for polarization when compared with the corresponding ALMO-EDA terms. We trace the larger 2-body followed by 3-body polarization errors to the Thole damping scheme used in AMOEBA, and although the width parameter in Thole damping can be changed to improve agreement with the ALMO-EDA polarization for points about equilibrium, the correct profile of polarization as a function of intermolecular distance cannot be reproduced. The results suggest that there is a need for re-examining the damping and polarization model used in the AMOEBA force field and provide further insights into the formulations of polarizable force fields in general. Published by AIP Publishing.