Local structural effects and related dynamics in supercritical ethanol. 2. Hydrogen-bonding network and its effect on single reorientational dynamics.
Local structural effects and related dynamics in supercritical ethanol. 2. Hydrogen-bonding network and its effect on single reorientational dynamics.
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超临界乙醇中的局部结构效应和相关动力学。
DOI：
10.1021/jp901489c
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
E. Guàrdia
中科院分区：
文献类型：
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作者：
Ioannis Skarmoutsos;E. Guàrdia
用分子动力学模拟技术系统地研究了超临界乙醇中的局域氢键网络及其可能与单一重定向动力学的相互作用。计算结果表明，计算的平均氢键数n(Hb)与计算的配位数N(C)具有相似的非线性密度依赖关系，这也表明了局域HB网络与sc乙醇的局域密度增大之间的相互关系。此外，还根据几个合适的时间关联函数研究了HB动力学。结果表明，HB动力学的密度依赖性与局域密度和驻留动力学有一些相似之处，对应于很短的长度尺度。此外，相互重定向对Hb动力学的影响似乎比相互扩散的影响更重要。最后，系统地研究了几种乙醇分子内载体的重定向动力学。从得到的结果中，我们可以观察到分子中几个重定向模式的动力学表现出显著的差异。此外，还研究了每个分子的Hb状态对这些动力学的影响，发现了显著的差异，特别是在Hb自由分子的动力学方面。
The local hydrogen-bonding (HB) network and its possible interconnection with the single reorientational dynamics in pure supercritical (sc) ethanol have been systematically investigated by employing molecular dynamics simulation techniques. The results obtained reveal a nonlinear density dependence of the calculated average number of hydrogen bonds n(HB), similar to that of the calculated coordination numbers N(c), signifying also the interrelation between the local HB network and the local density augmentation in sc ethanol. Additionally, the HB dynamics were investigated in terms of several appropriate time correlation functions. The results obtained reveal that the density dependence of HB dynamics has some similarities with local density and residence dynamics, corresponding to very short length scales. Moreover, the effect of mutual reorientation on HB dynamics seems to be more important than that of mutual diffusion. Finally, the reorientational dynamics of several intramolecular vectors of ethanol have been systematically studied. From the results obtained, we may observe that the dynamics of several reorientational modes in the molecule exhibit significant differences between them. Furthermore, the effect of the HB state of each molecule on these dynamics has also been studied, revealing significant differences, especially in the case of the dynamics of HB free molecules.