Effects of an externally applied electric field on orientation polarization of the water molecules at an insulator–solution interface were studied using sum-frequency generation (SFG) spectroscopy. Orientation of water molecules that have a structure causing a signal at ∼3100 cm–1 in the SFG spectra are strongly affected by an applied electric field. Moreover, the water dipole flips when an electric field is applied in the opposite direction of the electric field generated from the surface charge of a solid insulator (calcium fluoride). The required electric field is extremely low compared to that expected by the zeta potential, implying that the structure of the SFG signal is formed not on the calcium fluoride surface, where the electric field is expected to be the strongest, but further from the interface.
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机译:使用和频产生(SFG)光谱研究了外加电场对水分子在绝缘子-溶液界面的取向极化的影响。 SFG光谱中具有在〜3100 cm -1 sup>处引起信号的结构的水分子的取向会受到施加的电场的强烈影响。此外,当在与从固体绝缘体(氟化钙)的表面电荷产生的电场相反的方向上施加电场时,水偶极子翻转。与zeta电位所期望的电场相比,所需的电场极低,这意味着SFG信号的结构不是在氟化钙表面上形成的,该表面预计电场最强,但距离界面更远。
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