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.
