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. ***
