Studies of the Structure, Phase Transitions, and Dynamics ofAdsorbed Monolayers

利用两个互补散射的实验 技术将被用来解决各种问题， 目前对表面物理学感兴趣。 这些措施包括：1） 单分子膜中的新结构的研究 确定稳定它们的相互作用; 2） 准二阶集体振动激发的性质 三维（2D）分子固体;和3）相的研究 在吸附的单分子层中的跃迁， 体积或在2D中理论上可能更易处理。 的 实验将采用非弹性中子散射， 研究薄膜动力学和弹性中子衍射 和同步加速器X射线散射来探测膜结构。 在 在设计实验时，已经做出了相当大的努力， 将探头与感兴趣的系统相匹配， 在美国可用的设施。 后者包括一个 装有多数据探测器的中子衍射仪 密苏里州大学研究堆的采集系统 设施，最先进的三轴光谱仪， 布鲁克海文国家实验室和一个专门设计的超 在X射线束线处使用的高真空样品室 国家同步加速器光源 特别感兴趣的 将这种探针组合应用于吸附的 一种碳氢化合物，其单层结构对一种基本的 了解催化、润滑和粘附。

Experiments which utilize two complementary scattering techniques will be used to address a variety of problems of current interest in surface physics. These include: 1) the study of novel structures in molecular monolayers and the determination of the interactions which stabilize them; 2) the nature of collective vibrational excitations in quasi two- dimensional (2D) molecular solids; and 3) the study of phase transitions in adsorbed monolayers which either do not occur in bulk or which may be more tractable theoretically in 2D. The experiments will employ inelastic neutron scattering to investigate film dynamics and both elastic neutron diffraction and synchrotron x-ray scattering to probe film structure. In designing the experiments, considerable effort has been made to match the probe to the system of interest and to utilize the best facilities available in the United States. The latter include a neutron diffractometer equipped with a multidetector-data acquisition system at the University of Missouri Research Reactor Facility, state-of-the-art triple-axis spectrometers at Brookhaven National Laboratory, and a specially designed ultra- high vacuum sample chamber to be used at the x-ray beamline at the National Synchrotron Light Source. Of particular interest will be to apply this combination of probes to adsorbed hydrocarbon whose monolayer structure is crucial to a fundamental understanding of catalysis, lubrication and adhesion.