Ion-Atom Scattering Experiments: Low Energy

Abstract

This chapter outlines the physical principles and experimental methods used to investigate low energy ion-atom collisions. A low energy collision is here defined as one in which the initial ion-atom relative velocity is less than the mean orbital velocity 〈ve〉 of the electrons affected by the collision. For outer or valence electrons, 〈ve〉 ≃ vB, where vB =2.1877×108 cm/s is the Bohr velocity. In terms of the energy of a projectile ion, vB corresponds to 24.8 keV/N, where N is the projectile nuclear number (e.g., 16 for O+). The theory and results of ion-atom scattering studies are further discussed in Chapts. 37, 38, and 47 to 51. The focus here is on the experimental techniques. Since several of these depend on the characteristics of a specific process, the following section presents a summary of the physics of low-energy ion-atom collisions. See Chapts. 50 and 51 for more detailed information.