Theoretical investigation of the triple differential cross section in the nitrogen molecule ionization by electron and positron impact

Abstract

Calculations of the triple differential cross section (TDCS) for positron and electron impact ionization have been performed for the inner as well as the outer orbitals of nitrogen molecule, within a model developed for molecular targets and called M3CWZ. In this model, a full Coulomb wave scheme with variable charges to describe the continuum particles is used, taking into account the post collision interaction (PCI). Experiments performed in asymmetric geometries at large and lower recoil momentum have been investigated for the outer ($2{\sigma }_u$, $1{\pi }_u$and$3{\sigma }_g$) as well as the inner $2{\sigma }_g$ orbitals, comparison is then made between experimental data and theory. At intermediate impact energies (up to 700 eV), it is found that the M3CWZ model is able to predict the general trends of the TDCS for the outer orbitals at large recoil momentum when the residual ion plays substantial role, better than other sophisticated models. For the inner $2{\sigma }_g$ orbital the large intensity of the TDCS observed in the recoil region is not correctly reproduced by the present calculations. At lower 250 eV impact energy, a moderate agreement with the data is achieved for outer $3{\sigma }_g$orbital.