Scattering and Recoiling Spectrometry: An Ion's Eye View of Surface Structure

Abstract

Recent developments in ion-scattering spectrometry have led to a surface crystallography that is sensitive to all elements, including hydrogen. Time-of-flight techniques for the detection of atoms scattered and recoiled from surfaces in simple collision sequences, together with calculations of shadowing and blocking cones, can be used to make direct measurements of interatomic spacings and adsorption sites within an accuracy of </=0.1 angstrom. Time-of-flight detection of both neutrals and ions provides the high sensitivity necessary for nondestructive analysis. Structures are determined by monitoring the angular anisotropies in the scattered primary and recoiled target atom flux. Such surface and adsorption site determinations find application in such fields as catalysis, thin film growth, and interfaces.