Liquid structures of water, methanol, and hydrogen fluoride at ambient conditions from first principles molecular dynamics simulations with a dispersion corrected density functional.
Liquid structures of water, methanol, and hydrogen fluoride at ambient conditions from first principles molecular dynamics simulations with a dispersion corrected density functional.
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水、甲醇和氟化氢在环境条件下的液体结构，采用色散校正密度泛函的第一原理分子动力学模拟。
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发表时间：
2011
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通讯作者：
J. Siepmann
中科院分区：
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作者：
Matthew J. McGrath;I. W. Kuo;J. Siepmann
采用第一性原理分子动力学方法，在等压-等温系综（T = 300 K，p = 1 atm）中，采用Becke-Lee-Yang-Parr交换/关联泛函和格里姆的色散修正，研究了纯液态水、甲醇和氟化氢的氢键网络.虽然在这种电子结构理论水平下发现了水的准确密度，但氟化氢和甲醇的平均液体密度分别被高估了50%和25%。径向分布函数表明所有三种化合物的液相都有些过结构化。水分子中氢键的数量大约是甲醇和氟化氢的两倍，尽管水分子的内聚能与氢键数量的比值较低。氢键聚集体的分析显示，在氟化氢和甲醇中存在大多数线性链，在氟化氢的情况下，有一些稳定的环和链跨越模拟框。只有一个极小的部分较小的集群被发现的水，这表明它的氢键网络是显着更广泛。一种特殊形式的水，平均每个分子有两个氢键，产生的氢键环境与其他两种化合物明显不同。
Using first principles molecular dynamics simulations in the isobaric-isothermal ensemble (T = 300 K, p = 1 atm) with the Becke-Lee-Yang-Parr exchange/correlation functional and a dispersion correction due to Grimme, the hydrogen bonding networks of pure liquid water, methanol, and hydrogen fluoride are probed. Although an accurate density is found for water with this level of electronic structure theory, the average liquid densities for both hydrogen fluoride and methanol are overpredicted by 50 and 25%, respectively. The radial distribution functions indicate somewhat overstructured liquid phases for all three compounds. The number of hydrogen bonds per molecule in water is about twice as high as for methanol and hydrogen fluoride, though the ratio of cohesive energy over number of hydrogen bonds is lower for water. An analysis of the hydrogen-bonded aggregates revealed the presence of mostly linear chains in both hydrogen fluoride and methanol, with a few stable rings and chains spanning the simulation box in the case of hydrogen fluoride. Only an extremely small fraction of smaller clusters was found for water, indicating that its hydrogen bond network is significantly more extensive. A special form of water with on average about two hydrogen bonds per molecule yields a hydrogen-bonding environment significantly different from the other two compounds.