The resonant single-charge-transfer process for negative ions, $A^{-}+A\to A+A^{-}$, is considered at low energies. The exact asymptotic behavior of the energy separation $\Delta \mathrm{}\left(R\right)\mathrm{}$ of the symmetrical and antisymmetrical states of the quasimolecule $A_2^{-}$ is determined. In the adiabatic region, the transition probability of charge-exchange processes is determined by $\Delta \mathrm{}\left(R\right)\mathrm{}$. The general results are used to calculate cross sections for $A^{-}+A\to A+A^{-}$ reactions where $A$ is H, Na, K, Rb, and Cs. Comparison is made with the experimental data and with the calculations of other authors.

• Received 14 March 1969

DOI:https://doi.org/10.1103/PhysRev.186.89