Theory of Physically Adsorbed Layers

本文介绍了物理吸附薄层的结构和热力学的理论研究方案。主要目的是实现对几种吸附/衬底组合的定量理解，在这些组合中，最近的实验数据显示了附层晶格和衬底晶格的竞争空间周期性的影响。描述了几个主题，这些主题可以改进对吸附原子在衬底表面上横向运动的能垒的规范。所考虑的衬底是铂的(111)面、石墨的基面和氧化镁的(001)面。被吸附的物质包括氙气、氪以及分子氢和氮。这些计算包括氢和氢的基态的变分量子力学，以及近经典吸附的晶格动力学和晶胞模型近似。这项拟议的工作在很大程度上依赖于低能电子衍射、X射线衍射、热中子散射和热氦原子散射的改进所获得的实验数据。

A program of theoretical research on the structures and thermodynamics of thin physically adsorbed layers is described. The main goal is to achieve a quantitative understanding of a few adsorbate/substrate combinations in which recent experimental data show effects of the competing spatial periodicity of an adlayer lattice and the substrate lattice. Several topics are described which could lead to improved specification of the energy barriers to lateral motion of adsorbed atoms on the substrate surface. The substrates considered are the (111) face of platinum, the basal plane surface of graphite and the (001) face of magnesium oxide. The adsorbates include xenon, krypton and molecular hydrogen and nitrogen. The calculations include variational quantum mechanics for the ground state of hydrogen and deuterium and lattice dynamics and cell model approximations for the near classical adsorbates. The proposed work relies heavily on experimental data obtained from refinements of low energy electron diffraction, x-ray diffraction, thermal neutron scattering, and thermal helium atom scattering.