Physisorption Studies

物理吸附研究

• 批准号: 9004108
• 负责人: George Hess
• 金额: $ 20.12万
• 依托单位: University of Virginia Main Campus
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1990
• 资助国家: 美国
• 起止时间: 1990-07-01 至 1994-06-30
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9004108&HistoricalAwards=false
• 关键词: Physisorption; Studies

To study thermodynamic properties of multilayer films of various adsorbates on uniform surfaces of graphite and other substrates. The technique, currently used by them and by one group in Germany, combines ellipsometric measurement of coverage with vapor pressure measurement by conventional capacitance manometers or by modified manometers operating at low temperature adjacent to the sample. Among the phenomena which will be studied are surface roughening and surface melting behavior of krypton, xenon, and methane films on graphite, including detailed examination of the layer critical points and inverse critical points which occur in fourth and higher layers, at least for krypton; exploration of the phase diagrams of neon and hydrogen in the same thickness range; and wetting and layering behavior of other interesting systems, such as carbon monoxide on graphite. Other substrates will be examined besides graphite, including TiS2, TaSe2, and other layered dichalcogenides, cleaved surfaces of ionic crystals such as LiF and MgO, and gold films evaporated on mica. A number of improvements in the experimental apparatus will allow better precision in coverage and pressure measurement.

研究不同吸附剂在石墨和其他基底均匀表面上的多层膜的热力学性质。目前由他们和德国的一个小组使用的这项技术，结合了椭圆测量覆盖范围和蒸汽压力测量，通过传统的电容压力计或在靠近样品的低温下工作的改进压力计进行测量。将研究的现象包括石墨上的氪、氙和甲烷薄膜的表面粗化和表面熔化行为，包括对发生在第四层和更高层的层临界点和反临界点的详细检查，至少对于氪；同厚度范围内氖、氢的相图探讨还有其他有趣系统的润湿和分层行为，比如石墨上的一氧化碳。除石墨外，还将研究其他衬底，包括TiS2、TaSe2和其他层状二硫化物，离子晶体（如LiF和MgO）的切割表面，以及云母上蒸发的金膜。实验装置的一些改进将使覆盖范围和压力测量更加精确。