Fast ion beams from accelerators are traditionally associated with research in nuclear physics, or at GeV particle energies, in subatomic physics. This is to overlook the developments over the past three decades in the area of particle-solid interactions. Detailed studies of fast particle penetration including the fundamental processes of ion energy loss and ion scattering, and of correlated collison sequences which occur for particle trajectories in single crystals, have laid the foundations for broad application of ion beam methods to materials science and engineering. Throughout, important contributions have been made and continue to be made by Canadian laboratories. Fast ion beam techniques now provide powerful methods for thin film and surface microanalysis, likewise they are opening unique routes to the selective modification of materials.
Applications are rich in both chemistry and physics.
A brief overview of ion mobility theory and experiments is presented. Current interest in ion mobilities includes not only the testing of intermolecular potentials for atomic or small molecular ions but also includes the study of much larger ions, such as those of proteins, clusters, and organometallic compounds. A molecular dynamics method is introduced and aimed at understanding this latter class of ions. Comparisons are made with experiment and with previous calculations. In the unique environment at surfaces and interfaces, atoms give expression to magnetic behaviour in novel ways.