Ionization of the Noble Gases by Slow Positive Alkali Ions

The problem of the ionization of gases by impact of positive ions at low velocities is one in which it is necessary for a large amount of experimental evidence to be gathered before the theorist is able to hazard an intelligent guess at the processes involved. The material herein presented represents the essential advances that have been made in this field. As is usually the case it is impossible to say when and by whom investigations have begun on a particular problem. So it is with this problem. However, the history of its development up to a few years ago is one of a series of experiments giving either absolutely negative results, or results completely masked by secondary effects.