SURFACE STUDIES USING PARTICLE-BEAM-INDUCED DESORPTION AND MULTIPHOTON RESONANCE IONIZATION.

Summary form only given, as follows. Energetic particle beams are now important tools in a variety of areas ranging from chemical modification of electronic materials through reactive ion etching and ion implantation to probes of surface chemistry and high-molecular-weight mass spectrometry. Emphasis is placed on the fundamental aspects of the particle-solid interaction process and how these aspects may be utilized to understand the chemistry of reactions resulting from high-energy collisions. The experimental strategy is to perform energy and angle-resolved measurements on atoms and molecules desorbed from single-crystal surfaces. These measurements are made possible by a novel detector which utilizes the single-atom sensitivity of multiphoton resonance ionization, the position sensitivity of a microchannel plate, and the timing capabilities of a time-of-flight analysis. The measurements are then compared directly to results of molecular dynamics calculations of the particle impact event. These comparisons help the researcher formulate mechanisms of molecular cluster formation and elucidate the origin of angular anisotropies in the yields of desorbed species.