Structural Properties and Dynamics of Thiophene in Sub/Supercritical Carbon Dioxide from Car鈥揚arrinello Molecular Dynamics Simulations

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• 作者：Yongping Zeng ; Chunfeng Wang ; Yueyang Xu ; WenLin Xu ; Shengui Ju
• 刊名：Journal of Physical Chemistry B
• 出版年：2015
• 出版时间：July 9, 2015
• 年：2015
• 卷：119
• 期：27
• 页码：8573-8582
• 全文大小：591K
• ISSN：1520-5207

文摘

Structrual and dynamic properties of thiophene (C₄H₄S) in supercritical carbon dioxide were studied using Car鈥揚arrinello molecular dynamics simulations. The geometries and energies optimized for the thiophene鈥揅O₂ complex show a stable C鈥揌路路路O hydrogen bond interactions both in gas phase and in supercritical CO₂. The radial distribution functions of CO₂ around thiophene in the supercritical phase state show a correlation suggesting C鈥揌路路路O hydrogen bond and S路路路C interaction. Local structural properties of the mixtures were investigated by angular-radial distributions and spatial distribution functions. The results show a mutually parallel arrangement between the thiophene plane and CO₂ molecules at short distances and a high probability of the thiophene being located in the radial directions of the CO₂ molecules. The decay of orientational correlations at 318.15 K shows slower relaxation compared to those of 298.15 K for first and second rank correlations. The vibrations of CO₂ and thiophene molecules have been examined through an analysis of the velocity autocorrelation functions of the atoms. The C鈥揌 stretching modes of thiophene in the isolated configuration are less red-shifted and have a much narrower frequency range than that in the mixtures.