Structural properties of water: Comparison of the SPC, SPCE, TIP4P, and TIP5P models of water
Structural properties of water: Comparison of the SPC, SPCE, TIP4P, and TIP5P models of water
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DOI：
10.1063/1.2018637
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发表时间：
2005-09-08
影响因子：
4.4
通讯作者：
Zielkiewicz, J
中科院分区：
文献类型：
--
作者：
Zielkiewicz, J
在298 K下对SPC、SPCE、TIP 4P和TIP 5 P模型进行了分子动力学模拟。从这些结果中，我们确定以下数量：绝对熵使用两个粒子近似，平均寿命的氢键，平均数的氢键每个分子，和平均能量的氢键。从熵的计算中，我们发现，几乎所有的贡献，总熵来源于取向效应。此外，我们确定的总熵的贡献源自第一，第二，和更高的溶剂化壳。有趣的是，溶剂化壳层之间的界限清晰可见。第一溶剂化壳层（0.22 < r < 0.36 nm）对总熵贡献约43 J/mol K;第二溶剂化壳层（0.36 < r < 0.60 nm）贡献约12 J/mol K，而来自第三溶剂化壳层和其他溶剂化壳层的贡献非常小，总的来说约为2 J/mol K。这表明水分子在中心水分子周围的0.55-0.6 nm处是高度有序的，超过这个极限，有序性就会减弱。计算结果（熵和氢键）与实验数据进行比较，选择最佳的水模型。我们发现，SPC和TIP 4P模型再现最佳的实验值，我们建议这些模型的生物分子的水溶液的计算机模拟。(c)2005年美国物理学会。
Molecular-dynamics simulations were carried out for the SPC, SPCE, TIP4P, and TIP5P models of water at 298 K. From these results we determine the following quantities: the absolute entropy using the two-particle approximation, the mean lifetime of the hydrogen bond, the mean number of hydrogen bonds per molecule, and the mean energy of the hydrogen bond. From the entropy calculations we find that nearly all contributions to the total entropy originates from the orientation effects. Moreover, we determine the contributions to the total entropy which originate from the first, second, and higher solvation shells. It is interesting that the limits between solvation shells are clearly visible. The first solvation shell (0.22 < r < 0.36 nm) contributes approximately 43 J/mol K to the total entropy; the second solvation shell (0.36 < r < 0.60 nm) contributes approximately 12 J/mol K, while contributions from the third and other solvation shells are very small, approximately 2 J/mol K in summary. This indicates that water molecules are strongly ordered up to 0.55-0.6 nm around the central water molecule, and beyond this limit the ordering diminishes. The results of calculations (entropy and hydrogen bonds) are compared with the experimental data for the choosing of the best water model. We find that the SPC and TIP4P models reproduce the best experimental values, and we recommend these models for computer simulations of the aqueous solution of biomolecules. (c) 2005 American Institute of Physics.