Surface Structures of NaF and Na_2SO_4 Aqueous Solutions : Specific Effects of Hard Ions on Surface Vibrational Spectra
Surface Structures of NaF and Na_2SO_4 Aqueous Solutions : Specific Effects of Hard Ions on Surface Vibrational Spectra
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NaF 和 Na_2SO_4 水溶液的表面结构：硬离子对表面振动光谱的特定影响
DOI：
10.1021/jp3019777
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发表时间：
2012
期刊：
影响因子：
3.7
通讯作者：
A. Morita
中科院分区：
文献类型：
--
作者：
T. Imamura;Y. Mizukoshi;T. Ishiyama;A. Morita
我们用分子动力学(MD)模拟方法研究了NaF和Na2SO4水溶液的表面结构和频率谱。这些电解质溶液含有硬离子，它们的表面被认为没有离子物种。然而，这两种溶液的SFG光谱明显不同，这意味着不同的表面结构。目前的MD分析证实，所有的离子物种都从表面被排斥，尽管它们的实验SFG光谱被很好地重现。它们的表面结构的差异在亚表面区域观察到，其中在Na2SO4溶液中发生了轻微的电荷分离。SFG谱中的扰动不是由最顶层引起的，而是由表面较深区域的水取向引起的。
We elucidated surface structure and sum frequency generation (SFG) spectra of aqueous NaF and Na2SO4solutions by molecular dynamics (MD) simulation. These electrolyte solutions contain hard ions, and their surfaces are considered to be void of ion species. Nevertheless, the two solutions have shown remarkably different SFG spectra, implying different surface structure. The present MD analysis confirmed that all the ionic species are repelled from the surface, though their experimental SFG spectra are well reproduced. The difference in their surface structure is observed in the subsurface region, where slight charge separation occurs in the Na2SO4solution. The perturbation in the SFG spectra is not attributed to the topmost layer but to the water orientation in a fairly deep region of the surface.