Ion-ion mutual neutralization

The two-body ion-ion mutual neutralization reaction A++B-→A+B is an interesting and unusual member of the large family of electron capture (charge transfer) reactions. It is of theoretical interest because it has certain simplifying characteristics compared to most ion-neutral reactions. It is of practical interest because it occurs in any ionized gas where negative ions are formed and thus has important effects in electrical discharges, flames, lasers, and in the earth's ionosphere. In the last ten years considerable effort has been given to measurements of cross sections and rates for these reactions, and to improving the theoretical methods of treating them. This paper reviews the results of the various experimental and theoretical methods that have been employed to date, and also indicates some problem areas that are not yet adequately understood. (Auth.)