Studies of Physical Adsorption

成立了一个新材料研究小组，研究物理吸附薄膜中的物理吸附和相变的基本方面。这项研究的目的是研究物理吸附薄膜的结构和动力学，以及这些相的性质和它们之间的转变。这项研究分为五个主题：(1)石墨表面单层Ar膜的熔化，(2)双吸附体薄膜的相变，(3)简单气体在表征良好的沸石多孔介质中的性质，(4)弱结合衬底上单层和多层氦薄膜的特殊性质，(5)薄膜的脱附和氦原子散射。实验工作包括热容量测量、原位蒸汽压等温线研究、非弹性氦散射、高分辨率低能电子衍射、非弹性氦散射、中子散射、飞行时间解吸测量以及润湿和超流体研究。分子动力学计算机模拟被用来提供对薄膜和受限流体的吸附行为和相变的真实模拟。在该计划的理论推进中，使用势能模型和统计力学方法研究了吸附体系的相互作用势、原子-表面散射以及经典和量子跃迁。实验、计算模拟和理论的强耦合使得孤立的方法不可能取得进展。

A new Materials research Group is established to investigate fundamental aspects of physical adsorption and phase transitions in physisorbed films. The goals of the research are to study both the structure and kinetics of physisorbed films, and the nature of these phases and the transitions between them. The research is organized into five topics: (1) melting of monolayer argon films on graphite, (2) phase transitions of films of binary adsorbates, (3) properties of simple gases in a well- characterized zeolite porous medium, (4) unusual properties of monolayer and multilayer helium films on weak-binding substrates, (5) desorption and helium atom scattering of films. Experimental efforts include measurement of heat capacity, in-situ vapor pressure isotherm study, inelastic helium scattering, high- resolution low-energy electron diffraction, inelastic helium scattering, neutron scattering, time-of-flight desorption measurements, and wetting and superfluid studies. Molecular dynamics computer simulation is being used to provide realistic modelling of adsorbate behavior and phase transitions of thin films and confined fluids. Interaction potentials, atom-surface scattering, and classical and quantum transitions of adsorbate systems are being studied in the theoretical thrusts of the program using potential energy models and statistical mechanics approaches. The strong coupling of experiment, computational simulation and theory are making advances not possible by isolated approaches.