Laboratory measurements of ionospheric ion‐molecule reaction rates

The present status of laboratory measurements of ion‐molecule reactions of ionospheric importance is reviewed. Rate constants for most of the normal terrestrial E and F region reactions have been reliably measured at 300°K. Recently, some data have become available on the energy dependences of the most important of these binary positive ion reactions. In the case of D region reactions a great deal of new data on both positive and negative ion reaction rate constants has appeared in recent years. Both binary reactions and three‐body reactions are important in the D region, and important reactions still remain to be measured.