What is the Optimal Dipole Moment for Nonpolarizable Models of Liquids?
What is the Optimal Dipole Moment for Nonpolarizable Models of Liquids?
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DOI：
10.1021/acs.jctc.2c01123
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发表时间：
2023-03-28
影响因子：
5.5
通讯作者：
Cole, Daniel J.
中科院分区：
文献类型：
--
作者：
Jorge, Miguel;Barrera, Maria Cecilia;Milne, Andrew W.;Ringrose, Chris;Cole, Daniel J.
在经典的非极化模型中，静电相互作用通常通过将固定的部分电荷分配给相互作用位点来描述。尽管多年来提出了许多方法和理论的部分电荷分配，一个基本的问题是什么是正确的极化度，一个固定电荷模型应该拥有提供最佳的相互作用（包括感应效应）的平衡，并产生最好的描述的势能面的液相？我们从两个独立的观点来处理这个问题：量子力学BEspoke（QUBE）方法，其从具有最小经验拟合的从头计算为单个分子分配定制的力场参数，以及极化一致性方法（PolCA）力场，基于力场参数的经验拟合，强调通过严格考虑参数化过程中的极化效应的可转移性。我们表明，这两种方法产生一致的答案，上述问题，即，该模型的偶极矩应该是大约一半之间的气体和液相。然而，至关重要的是，参考液相偶极子需要使用明确考虑平均场和局部贡献极化的方法进行估计。特别是，连续介质模型是不足以达到这一目的，因为它们不能考虑局部效应，因此大大低估了分子的极化程度。这些观测结果对非极化模型的发展、验证和测试具有深远的影响。
In classical nonpolarizable models, electrostatic interactions are usually described by assigning fixed partial charges to interaction sites. Despite the multitude of methods and theories proposed over the years for partial charge assignment, a fundamental question remains—what is the correct degree of polarization that a fixed-charge model should possess to provide the best balance of interactions (including induction effects) and yield the best description of the potential energy surface of a liquid phase? We address this question by approaching it from two separate and independent viewpoints: the QUantum mechanical BEspoke (QUBE) approach, which assigns bespoke force field parameters for individual molecules from ab initio calculations with minimal empirical fitting, and the Polarization-Consistent Approach (PolCA) force field, based on empirical fitting of force field parameters with an emphasis on transferability by rigorously accounting for polarization effects in the parameterization process. We show that the two approaches yield consistent answers to the above question, namely, that the dipole moment of the model should be approximately halfway between those of the gas and the liquid phase. Crucially, however, the reference liquid-phase dipole needs to be estimated using methods that explicitly consider both mean-field and local contributions to polarization. In particular, continuum dielectric models are inadequate for this purpose because they cannot account for local effects and therefore significantly underestimate the degree of polarization of the molecule. These observations have profound consequences for the development, validation, and testing of nonpolarizable models.
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影响因子：
4.1
作者：
BENNETT, CH
通讯作者：
BENNETT, CH
影响因子：
2.8
作者：
BEUTLER, TC;MARK, AE;VANGUNSTEREN, WF
通讯作者：
VANGUNSTEREN, WF
影响因子：
2.1
作者：
Eggimann, Becky L.;Sunnarborg, Amara J.;Siepmann, J. Ilja
通讯作者：
Siepmann, J. Ilja
影响因子：
2.9
作者：
HOOVER, WG
通讯作者：
HOOVER, WG
影响因子：
4.4
作者：
Horn, HW;Swope, WC;Head-Gordon, T
通讯作者：
Head-Gordon, T