Introduction

Abstract

Studies of the fundamental interactions between positively charged ions and neutral atoms, molecules and electrons constitute a significant, and important, part of contemporary atomic and molecular physics. Much of the importance attributed to this sub-field stems from an awareness that has grown over the last two decades that qualitative and quantitative knowledge of the physics of ionic collisions is a prerequisite for gaining an understanding of a wide variety of natural and man-made phenomena. For instance, the need for ion-electron and ion-atom collision information is now well recognized in seeking to elucidate the mechanisms governing the energy budget of high temperature astrophysical plasmas or within a thermonuclear fusion device, or for attaining an understanding of the processes giving rise to the formation and destruction of atomic and molecular species in cold interstellar space, and in terrestrial and planetary atmospheres. There are numerous other applications also; a comprehensive overview of the applied scope of ion collision physics can be found in the mammoth five-volume treatise [1.1] produced by Massey et al. These volumes highlight the importance of the subject in diverse areas, such as geophysics and astrophysics, controlled nuclear fusion, laser chemistry, condensed matter physics and a gamut of other applications, ranging from detectors used in high energy physics, MHD power generation, combustion chemistry and the study of flames and discharges to, unfortunately, military applications of high powered laser systems, high energy particle beams, precision timing and atomic magnetometers and nuclear magnetic resonance gyroscopes.