Ion Segregation in Aqueous Solutions

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• 作者：Hongtao Bian ; Jiebo Li ; Qiang Zhang ; Hailong Chen ; Wei Zhuang ; Yi Qin Gao ; Junrong Zheng
• 刊名：The Journal of Physical Chemistry B
• 出版年：2012
• 出版时间：December 13, 2012
• 年：2012
• 卷：116
• 期：49
• 页码：14426-14432
• 全文大小：444K
• 年卷期：v.116,no.49(December 13, 2012)
• ISSN：1520-5207

文摘

Microscopic structures and dynamics of aqueous salt solutions were investigated with the ultrafast vibrational energy exchange method and anisotropy measurements. In KSCN aqueous solutions of various concentrations, the rotational time constants of SCN^{鈥?/sup> anions are proportional to the viscosities of the solutions. However, the reorientation dynamics of the water molecules are only slightly affected by the solution viscosity. With the addition of strongly hydrated F鈥?/sup> anions, the rotations of both SCN鈥?/sup> anions and water molecules slow down. With the addition of weakly hydrated I鈥?/sup> anions, only the rotation of SCN鈥?/sup> anions slows down with that of water molecules unaffected. Vibrational energy exchange measurements show that the separation among SCN鈥?/sup> anions decreases with the addition of F鈥?/sup> and increases with the addition of I鈥?/sup>. The series of experiments clearly demonstrate that both structures and dynamics of ion and water are segregated in the strong electrolyte aqueous solutions.}