Festersen Sven, Hrkac Stjepan B, Koops Christian T, Runge Benjamin, Dane Thomas, Murphy Bridget M, Magnussen Olaf M
Institute for Experimental and Applied Physics, Kiel University, Kiel, Germany.
ESRF, The European Synchrotron, 71 Avenue des Martyrs, 38000 Grenoble, France.
J Synchrotron Radiat. 2018 Mar 1;25(Pt 2):432-438. doi: 10.1107/S1600577517018057. Epub 2018 Feb 16.
X-ray reflectivity studies of the structure of liquid-vapour and liquid-liquid interfaces at modern sources, such as free-electron lasers, are currently impeded by the lack of dedicated liquid surface diffractometers. It is shown that this obstacle can be overcome by an alternative experimental approach that uses the natural curvature of a liquid drop for variation of the angle of incidence. Two modes of operation are shown: (i) sequential reflectivity measurements by a nanometre beam and (ii) parallel acquisition of large ranges of a reflectivity curve by micrometre beams. The feasibility of the two methods is demonstrated by studies of the Hg/vapour, HO/vapour and Hg/0.1 M NaF interface. The obtained reflectivity curves match the data obtained by conventional techniques up to 5α in micro-beam mode and up to 35α in nano-beam mode, allowing observation of the Hg layering peak.
在诸如自由电子激光等现代光源下，对液 - 气和液 - 液界面结构进行X射线反射率研究，目前因缺乏专用的液体表面衍射仪而受阻。研究表明，通过一种替代实验方法可以克服这一障碍，该方法利用液滴的自然曲率来改变入射角。展示了两种操作模式：（i）通过纳米光束进行连续反射率测量，以及（ii）通过微米光束并行采集大范围的反射率曲线。通过对汞/蒸汽、水/蒸汽和汞/0.1M氟化钠界面的研究证明了这两种方法的可行性。在微光束模式下，所获得的反射率曲线与传统技术获得的数据在高达5α时匹配，在纳米光束模式下高达35α时匹配，从而能够观察到汞的分层峰。
