采用和频振动光谱（SFG）测量系统研究卤化物负离子对1-丁醇单层/水界面结构的影响

       Halide ions in seawater have been recognized as reactants in ozone depletion processes [1]. However, a detailed effect of halogen ion on the water surface structure has not been suggested due to the lack of tools to probe liquid surfaces specifically. As ultrafast laser technology has been developed recently, the sum-frequency generation vibrational spectroscopy (SFGVS) gives not only static information on surfaces but also dynamic properties of surface molecules [2].
       Sum-frequency generation (SFG) is a second-order nonlinear optical process that has an intrinsic sensitivity to the struture at surfaces and interfaces. In the SFVS we can control the polarization of both two incident waves as well as the output (sum-frequency) wave. By choosing an appropriate polarization combination for each SFG measurement we can also get the information of molecular orientation at the surface or interface.
      Molecules like fatty acids, lipids, and long-chain alcohols, which have both hydrophobic and hydrophilic parts, can form a Langmuir monolayer on water surface [3]. The structure of Langmuir monolayers resembles biological membranes and becomes a good research model for 2-dimensional systems. Normally, the hydrogen bondings between the interfacial water molecules and the hydrophilic head groups help form the Langmuir monolayer. In general, the presence of dissolved ions in water subphase affects the molecular orientation and the structure of the interfacial layers, but until recently the mechanism of this process has not yes become clear.
      In order to gain an insight into the impact of halide anions on the interfacial layers, in this report we use the SFGVS technique to investigate the structure of the 1-Butanol monolayer/water interface with various halide anions of Cl¯, I¯, and F¯ dissolved in the water subphase. affects the molecular orientation and the structure of the interfacial layers, but until recently the mechanism of this process has not yes become clear. 

       In order to gain an insight into the impact of halide anions on the interfacial layers, in this report we use the SFGVS technique to investigate the structure of the 1-Butanol monolayer/water interface with various halide anions of Cl¯, I¯, and F¯ dissolved in the water subphase.