Atomic beam techniques are used to measure the experimental differential cross sections of the chemi-ionization in sodium atom-iodine atom collisions in the electronvolt range.
We interpret the experimental methods thus obtained using the following theoretical methods . We try to explain this chemi-ionization process by means of a semiclassical atom-atom model for ion-pair formation, which is based on transitions between electronically coupled states of the system, in particular Landau-Zener transitions. In addition, the phenomenon of rotational coupling is taken into account. The differential cross sections are calculated, from the states of the system, via the deflection function, using the stationary phase approximation, the uniform approximation and JWKB phase shifts .