Structure Analysis of Solution Surface by Photoelectron Yield XAFS Method.

X射线吸收精细结构谱（XAFS）是对非晶态样品和液体进行短程结构分析的有力工具。在这项研究中，它的应用扩展到空气/水界面的化学物种。在全反射条件下，单色化X射线束以1 mrad的掠入射角入射到溶液池中。该细胞包含一个66毫米× 216毫米槽冷却到1？A1 C，并且电池充满大气压下的氦气。表面物种的XAFS通过检测转换电子流或氦离子流来确定。在0.1mM的硬脂酰三甲基溴化铵水溶液中，Br的K边吸收信号很强。通过透射法，光谱与本体溶液的光谱不同。

The X-ray absorption fine structure (XAFS) spectroscopy is a powerful tool for the short range structure analyzes of amorphous samples and liquids. In this study its application is extended to the chemical species at air/water interface. The surface active ions and molecules segregated at the solution surface are playing important role in the processes of solvent extraction, phase -transfer, and the formation of the Langmuir-Blodgett film, although almost nothing is known about the solvation structures of the surface species.The monochromatized X-ray beam was introduced into the solution cell at a grazing incidence angle of 1mrad under the total-reflection condition. The cell contains a 66mm x 216mm trough which is cooled to 1? A1C and the cell is filled with helium gas at an atmospheric pressure. The XAFS of the surface species was determined by detecting the conversion electron current or the helium ion current. Stearyltrimethylammonium bromide aqueous solution at 0.1mM concentration gave quite an intense signal for Br K-edge absorption. The spectrum was different from that of bulk solution by the transmission method.