Zero range Fermi approach in negative ion detachment

The zero range potential method is a natural approach to describe the processes involving negative ions. The low energy part of the detached electrons energy distribution obtained by this method agrees reasonably well with the experimental results. Some generalizations of the method are possible, allowing one to consider the relative motion of colliding atoms and ions quantum-mechanically, to treat the weakly-bound p-electrons and to apply the theory to the associative detachment processes. (Auth.)