NONDISSOCIATIVE AND DISSOCIATIVE IONIZATION OF NITROGEN MOLECULES BY POSITRON-IMPACT

The cross sections for direct and total dissociative and non-dissociat ive ionization of the nitrogen molecule by positron impact have been m easured for projectile energies from threshold to 2000 eV. The results are compared with corresponding data for impact of electrons, protons and antiprotons. The comprehensive model which during recent years ha s been developed to explain the behaviour of the single- and multiple- ionization cross sections of atoms by charged particle impact was foun d to also apply for this case of a molecular target. In particular, th e interference and factorization models which have been found to expla in important features of the cross sections for double ionization of a toms apply also to the dissociative ionization of nitrogen molecules.