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arXiv 1707.05403cond-mat.softphysics.chem-phphysics.comp-ph
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高浓度氯化锂水溶液中经典原子间相互作用势的比较

A comparison of classical interatomic potentials applied to highly concentrated aqueous lithium chloride solutions

Ildikó Pethes

摘要:

采用经典分子动力学模拟研究了氯化锂水溶液的高浓度行为。检查了基于12-6 Lennard-Jones模型的各种力场,参数化为不可极化的水溶剂分子(SPC/E,TIP 4P,TIP 4PEw)。在四个不同的盐浓度的离子-水相互作用模型的29个组合进行了检查。密度,静态介电常数和自扩散系数进行了计算。从不同力场得到的结果分散在很宽的值范围内。中子和X射线加权结构因子也计算出径向分布函数,并与实验数据进行了比较。有人发现,计算和实验曲线之间的协议是相当差的几个调查潜在的模型,即使他们中的一些人以前已被应用在计算机模拟。没有一个调查的模型产生令人满意的结果,所有的测试量。只有两个参数集提供了可接受的预测高度浓缩的氯化锂水溶液的结构。用于调整潜在参数的一些方法,例如Aragones的方法[Aragones等人,J.Phys.Chem.B118(2014)7680]和Pluharova [Pluharova等人,J.Phys.Chem.A117(2013)11766];这里呈现的模拟强调了它们的有用性。这些精制方法适合于获得更合适的离子/水电位。

英文摘要:

Aqueous lithium chloride solutions up to very high concentrations were investigated in classical molecular dynamics simulations. Various force fields based on the 12-6 Lennard-Jones model, parametrized for non-polarizable water solvent molecules (SPC/E, TIP4P, TIP4PEw), were inspected. Twenty-nine combinations of ion-water interaction models were examined at four different salt concentrations. Densities, static dielectric constants and self-diffusion coefficients were calculated. Results derived from the different force fields scatter over a wide range of values. Neutron and X-ray weighted structure factors were also calculated from the radial distribution functions and compared with experimental data. It was found that the agreement between calculated and experimental curves is rather poor for several investigated potential models, even though some of them have previously been applied in computer simulations. None of the investigated models yield satisfactory results for all the tested quantities. Only two parameter sets provide acceptable predictions for the structure of highly concentrated aqueous LiCl solutions. Some approaches for adjusting potential parameters, such as those of Aragones [Aragones et al., J. Phys. Chem. B 118 (2014) 7680] and Pluharova [Pluharova et al, J. Phys. Chem. A 117 (2013) 11766], were tested as well; the simulations presented here underline their usefulness. These refining methods are suited to obtain more appropriate ion/water potentials.

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