An estimating formula for ion–atom association rates in gases

Abstract
We derive a simple estimating formula for rate coefficients of three‐body ion atom association in gases and compare its predictions to experimental data on ion association and three‐body radiative charge transfer reactions of singly‐ and doubly‐charged rare‐gas ions. The formula appears to reproduce most experimental data quite well. It may be useful for estimating the rates of reactions that have not been studied in the laboratory.