Surface Chemistry with Ion Beams and Lasers

该项目涉及进行广泛的实验，旨在加强离子束用于表面化学研究的使用。这些实验的目的是(I)阐明离子/固体碰撞的基本方面，(Ii)利用(I)中获得的基本信息来表征固体表面的化学和结构，以及(Iii)优化离子束在表面痕量分子分析和亚微米成像中的应用。多光子共振电离光谱的使用将使中性物质能够以时间和空间分辨率被电离，方法是使用可移动的质谱仪来测量产生的二次离子的轨迹。这将使测量中性分子、激发的中性分子和从定义明确的表面上解吸的离子受到离子轰击成为可能。实验结果将与使用分子动力学模拟的理论模型进行比较。新的实验几何构型将通过使用阴影锥体增强解吸来确定。还将在表面的痕量分子分析以及亚微米原子和分子成像方面进行新的实验。在分析和表面化学的一般领域的研究，重点介绍高能离子束(能量为几千电子伏特)在表面化学研究中的应用。这些实验有望提供迄今为止最完整的离子/固体相互作用的图景，确定表面化学几何的新方法，表面痕量分子分析的新方法，以及表面原子和分子成像的新方法。这些研究成果将在高分子质谱学、天体物理学、聚变反应堆设计、离子注入和电子材料刻蚀等不同领域得到广泛应用。

The project involves performing an extensive range of experiments designed to enhance the use of ion beams for the study of surface chemistry. These experiments are designed to (i) elucidate the fundamental aspects of ion/solid collisions, (ii) to characterize the chemistry and structure of solid surfaces using the basic information obtained in (i), and (iii) to optimize the application of ion beams in trace molecular analysis of surfaces and in submicron imaging. The use of multiphoton resonance ionization spectroscopy will enable neutral species to be ionized with both temporal and spatial resolution by using a movable mass spectrometer to measure the trajectories of the secondary ions produced. This will enable the measurement of neutrals, excited neutrals, and ions desorbed from well-defined surfaces subjected to ion bombardment. The experimental results will be compared with a theoretical model which uses molecular dynamics simulations. New experimental geometries will be determined by the use of shadow-cone enhanced desorption. New experiments in the trace molecular analysis of surfaces and in submicron atomic and molecular imaging will also be performed. %%% The research, in the general area of Analytical and Surface Chemistry, focuses on the use of energetic ion beams (of several thousand electron volts in energy) in surface chemistry research. These experiments promise to provide the most complete picture so far developed of ion/solid interactions, new approaches to the determination of surface chemical geometries, new methods for trace molecular analysis of surfaces, and new approaches to the atomic and molecular imaging of surfaces. The results from these studies should find widespread applications in such diverse fields as high molecular weight mass spectrometry, astrophysics, fusion reactor design, and ion implantation and etching of electronic materials.