In recent years several measurements have been performed for total cross sections for chemi-ionisation in the inelastic-collision processes A + B -> A+ + B- as well as for the inverse neutralization , , , . In the research programme from which this article issues , total cross sections have been measured, using electronvolt molecular beam techniques , for collisions between alkali atoms and halogen molecules , alkali atoms and , alkali atoms and , and . The total cross sections of alkali atoms and and have also been measured as a function of the secondary beam temperature .
These cross sections are interpreted tentatively in terms of a simple atom-atom model , according to which the transition to the ionic state takes place via a crossing of the neutral and ionic ground states, which is passed twice in a collision. The transition probability is given by the Landau-Zener formula.
Here we report the relative differential cross sections of some alkali atom-halogen molecule charge-transfer collisions .