IONIZATION OF THE N-2 3-SIGMA(G) ORBITAL BY ELECTRON-IMPACT STUDIED BY ASYMMETRIC (E, 2E) EXPERIMENTS

Absolute triple differential cross sections (TDCS) for the ionization of molecular nitrogen by congruent-to 300 eV electron impact have been measured in a coplanar asymmetric arrangement. Two different values of the energy loss, DELTA-E = 25.6 and 34 eV, have been chosen in order to investigate the ionization mechanism in an energy region where the resonant channel 3-sigma(g) --> epsilon-sigma(u), epsilon-pi(u) competes with the direct process. For each DELTA-E the TDCS have been measured at two momentum transfers, K = 0.7 and 0.35 au, in order to approach the dipolar limit. Theoretical models for molecular TDCS are lacking, therefore the present results are qualitatively compared to TDCS of He obtained under analogous kinematics.