Cut-off radius effect of the isotropic periodic sum method for polar molecules in a bulk water system
Cut-off radius effect of the isotropic periodic sum method for polar molecules in a bulk water system
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本体水系统中极性分子各向同性周期和法的截止半径效应
DOI：
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
K. Yasuoka
中科院分区：
文献类型：
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作者：
Kazuaki Z. Takahashi;T. Narumi;K. Yasuoka
分子动力学模拟已被应用于水的极性分子（IPSp）的各向同性周期和（IPS）的方法（IPSn）的正常IPS方法和埃瓦尔德和评估的扩散系数和液体结构进行比较。在我们以前的研究中，我们已经应用了IPSn方法的散装水，发现径向分布函数g（r）的显着偏差。在这项工作中，IPSp给出了一个很好的估计的势能和自扩散系数的截止半径，rc，大于2.2 nm，同时避免了显着的偏差g（r）出现在IPSn的情况下。计算了与距离相关的柯克伍德因子Gk（r），截断类截断方法（如截断有或无开关函数和反应场）对偶极-偶极关联的截断显示出严重的缺陷。这是通过将形状与埃瓦尔德总和的形状进行比较来观察到的。Gk（r）与Ewald和的Gk（r）有很大的偏差。然而，IPSp方法的Gk（r）的误差远小于其它典型的类截止值方法。我们的结论是IPSP方法是一个足够准确的技术，用于估计传输系数和水的液体结构在一个均匀的系统在长的截止距离。
Molecular dynamics simulation has been applied for water to compare the isotropic periodic sum (IPS) method for polar molecules (IPSp) to the normal IPS (IPSn) method and the Ewald sum by evaluating the diffusion coefficient and liquid structure. In our previous study, we have applied the IPSn method for bulk water and found notable deviation of the radial distribution function g(r). In this work, the IPSp gives a good estimation for the potential energy and the self-diffusion coefficient at a cut-off radius, r c, greater than 2.2 nm while avoiding the notable deviation of g(r) which appeared in the case of IPSn. The distance-dependent Kirkwood factor G k (r) was also calculated, and the truncation of a long-range interaction of the cut-off-like method (such as cut-off with or without the switch function and the reaction field) shows serious shortcomings for dipole–dipole correlations in bulk water systems. This was observed by comparing the shape to that of the Ewald sum. G k (r) of the cut-off-like method greatly deviates from that of the Ewald sum. However, the discrepancy of G k (r) for IPSp method was found to be much less than that of other typical cut-off-like methods. We conclude that the IPSp method is an adequately accurate technique for estimating transport coefficients and the liquid structure of water in a homogeneous system at long cut-off distances.
极性系统静电相互作用的各向同性周期和。
DOI：
10.1063/1.3160730
发表时间：
2009
期刊：
The Journal of chemical physics
影响因子：
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作者：
Wu,Xiongwu;Brooks,BernardR
通讯作者：
Brooks,BernardR