Ethylene glycol revisited: Molecular dynamics simulations and visualization of the liquid and its hydrogen-bond network

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• 作者：Alex ; er Kaiser ; Oksana Ismailova ; Antti Koskela ; Stefan E. Huber ; Marcel Ritter ; Biagio Cosenza ; Werner Benger ; Renat Nazmutdinov ; Michael Probst
• 关键词：Ethylene glycol ; Molecular dynamics ; OPLS-AA force fields ; Hydrogen-bonds ; Visualization
• 刊名：Journal of Molecular Liquids
• 出版年：January, 2014
• 年：2014
• 卷：189
• 期：Complete
• 页码：20-29
• 全文大小：1968 K

文摘

Molecular dynamics simulations of liquid ethylene glycol described by the OPLS-AA force field were performed to gain insight into its hydrogen-bond structure. We use the population correlation function as a statistical measure for the hydrogen-bond lifetime. In an attempt to understand the complicated hydrogen-bonding, we developed new molecular visualization tools within the Vish Visualization shell and used it to visualize the life of each individual hydrogen-bond. With this tool hydrogen-bond formation and breaking as well as clustering and chain formation in hydrogen-bonded liquids can be observed directly. Liquid ethylene glycol at room temperature does not show significant clustering or chain building. The hydrogen-bonds break often due to the rotational and vibrational motions of the molecules leading to an H-bond half-life time of approximately 1.5 ps. However, most of the H-bonds are reformed again so that after 50 ps only 40% of these H-bonds are irreversibly broken due to diffusional motion. This hydrogen-bond half-life time due to diffusional motion is 80.3 ps. The work was preceded by a careful check of various OPLS-based force fields used in the literature. It was found that they lead to quite different angular and H-bond distributions.