Thermodynamics and Kinetics of Fluids on Weak Binding Substrates

最近发现碱金属表面与氦的相互作用非常弱，这为研究润湿转变提供了一个模型系统。提出的研究进一步利用氦-碱金属系统来研究表面流体的热力学和动力学的基本问题。实验大致分为基于石英微天平吸附等温线的热力学测量和使用光学技术的热力学和动力学测量。微平衡技术将用于研究氦-3在低温下对铯的作用，以寻找由于费米统计而预测的润湿效应。将研究铷和氢衬底上的氦-4，以检验T=0预润湿的可能性，以及共存超流体表面相的可能性。光学技术将用于研究具有三相接触线的超流体液滴和超流的性质。润湿是一种普遍存在的现象，它支配着从晶体生长到液滴扩散的过程。最近发现碱金属表面与氦的相互作用非常弱，这为研究润湿转变提供了一个模型系统。本研究将进一步利用氦/碱金属体系来研究表面流体热力学和动力学的基本问题。实验大致分为基于石英微天平吸附等温线的热力学测量和使用光学技术的热力学和动力学测量。微天平将用于研究氦对铯的润湿，寻找量子效应。光学技术将用于研究超流体液滴和有边缘的超流体流动。＊＊＊

9623976 Taborek The recent discovery that alkali metal surfaces interact very weakly with helium has provided a model system for the study of wetting transitions. The proposed research further exploits Helium-alkali metal systems to study fundamental issues of the thermodynamics and kinetics of fluids on surfaces. The experiments are divided approximately equally between thermodynamic measurements based on adsorption isotherms using quartz microbalances, and thermodynamic and kinetics measurements using optical techniques. The microbalance technique will be used to study Helium-3 on Cesium at low temperature to look for predicted wetting effects due to Fermi statistics. Helium-4 on Rubidium and Hydrogen substrates will be studied to examine the possibility of T=0 prewetting, and the possibility of coexisting superfluid surface phases. Optical techniques will be used to investigate the properties of superfluid drops and super flows with a three-phase contact line. %%% Wetting is a ubiquitous phenomenon which governs processes ranging from crystal growth to spreading of droplets. The recent discovery that alkali metal surfaces interact very weakly with helium has provided a model system for the study of wetting transitions. The proposed research further exploits Helium/alkali metal systems to study fundamental issues of the thermodynamics and kinetics of fluids on surfaces. The experiments are divided approximately equally between thermodynamic measurements based on adsorption isotherms using quartz microbalances, and thermodynamic and kinetics measurements using optical techniques. Microbalances will be used to study Helium on Cesium look for quantum effects in wetting. Optical techniques will be used to study superfluid droplets and superfluid flows with edges. ***