Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity
Surface layering and melting in an ionic liquid studied by resonant soft X-ray reflectivity
复制标题
DOI：
10.1073/pnas.1211749110
复制
发表时间：
2013-03-05
影响因子：
11.1
通讯作者：
Deutsch, Moshe
中科院分区：
文献类型：
--
作者：
Mezger, Markus;Ocko, Benjamin M.;Deutsch, Moshe
用互补法研究了离子液体[C(18)mim](+)[FAP]（-）在其自由表面附近的分子尺度结构。x射线吸收光谱和软x射线共振反射率揭示了深度衰减的近地表层状结构。从能量依赖的软x射线反射率数据中以亚分子分辨率提取元素特定的界面剖面。温度相关的硬x射线反射率、小角和广角x射线散射以及红外光谱揭示了层状区域的一个有趣的熔化机制，其中烷基链熔化驱动了表面层间距的负热膨胀。
The molecular-scale structure of the ionic liquid [C(18)mim](+)[FAP](-) near its free surface was studied by complementary methods. X-ray absorption spectroscopy and resonant soft X-ray reflectivity revealed a depth-decaying near-surface layering. Element-specific interfacial profiles were extracted with submolecular resolution from energy-dependent soft X-ray reflectivity data. Temperature-dependent hard X-ray reflectivity, small-and wide-angle Xray scattering, and infrared spectroscopy uncovered an intriguing melting mechanism for the layered region, where alkyl chain melting drove a negative thermal expansion of the surface layer spacing.