Adsorption on Weak Binding Substrates

弱结合基质上的吸附

• 批准号: 9223775
• 负责人: Peter Taborek
• 金额: $ 36万
• 依托单位: University of California-Irvine
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-08-01 至 1996-07-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9223775&HistoricalAwards=false
• 关键词: Adsorption; Weak; Binding; Substrates

9223775 Taborek This research project focuses on fundamental studies of adsorbed films of hydrogen, helium and neon on alkali metals and frozen hydrogen. The binding between the films and the substrates is weak, and as a result the adsorbed films display phases and phase transitions that do not occur on strong binding substrates (where the binding energy of the first few layers of adsorbate to the substrate is larger than the binding energy of the adsorbate to itself). Theoretical analysis indicates that these systems represent the entire range of weak binding behavior. The emphasis will be on the determining the dependence of features of the prewetting phase diagram on the adsorbate-substrate and adsorbate- adsorbate interaction parameters and on understanding the interplay between prewetting and bulk phase transitions, inducing superfluid onset in helium and the triple and critical points for the classical systems. The predominant technique will be the measurement of adsorption isotherms using microbalances supplemented by calorimetry and third sound. %%% The behavior of adsorbed films of liquid on solid surfaces is of interest from both fundamental and technical viewpoints. The study of the behavior of liquid films as they wet surfaces is complicated by the presence of various impurities at normal temperatures. This research will investigate the wetting of a range of surfaces by helium, hydrogen and neon. These films require ultralow temperatures, where impurity effects are essentially absent. The research will test recent theoretical predictions that suggest that the surface behavior of the various films will include unusual phase transitions that can be investigated by sensitive calorimety and microbalance techniques. The research will test these theories and potentially lead to films with new properties that may suggest new technological applications. ***

小行星9223775 本研究项目的重点是氢、氦和氖在碱金属和冷冻氢上的吸附膜的基础研究。 膜和基材之间的结合较弱，因此吸附膜显示出在强结合基材上不会发生的相和相变（其中吸附物的前几层与基材的结合能大于吸附物与自身的结合能）。 理论分析表明，这些系统代表了整个范围的弱结合行为。 重点将是确定的依赖关系的特征的预湿相图上的吸附质-基板和吸附质-吸附质的相互作用参数和理解之间的相互作用的预湿和散装相变，诱导超流开始在氦和三重和临界点的经典系统。 主要技术将是使用微量天平测量吸附等温线，并辅以量热法和第三声。 固体表面上的液体吸附膜的行为从基础和技术的观点来看都是令人感兴趣的。 由于常温下存在各种杂质，对液体膜润湿表面时的行为的研究变得复杂。 这项研究将调查一系列表面的润湿氦，氢和氖。 这些薄膜需要超低温，在那里杂质效应基本上是不存在的。 这项研究将测试最近的理论预测，这些预测表明，各种薄膜的表面行为将包括不寻常的相变，可以通过灵敏的量热和微量天平技术进行研究。 这项研究将测试这些理论，并可能导致具有新特性的薄膜，这些新特性可能暗示新的技术应用。 ***