Separation of ions with the same charge to mass ratio from a collision experiment

Same atomic collision experiments lead to ions having identical q/m ratio, as well as average velocity, so that standard electric and magnetic analyzers are not able to identify them separately. This situation occurs;si for instance, in electron interaction with molecular monocations (A(2)(+)) producing A(2)(2+) (direct ionization) and A(+) (dissociation or dissociative ionization). Due to the transfer of internal energy to the kinetic energy of the fragments, they usually have a wider angular and energy distribution in the laboratory frame, compared to direct ionization. By use of a specially designed animated crossed beams apparatus, we are able to separate ionization and dissociation fragments. Here the preliminary results of cross sections measurements for electron impact on the N-2(2+) and N+ ions, is reported