Electron impact dissociation and ionization of N-2(+)

Absolute cross sections for electron impact ionization, dissociative excita tion (DE) and dissociative ionization of N-2(+) ions are measured in the en ergy range from threshold to 2500 eV. The animated crossed electron-ion bea m method has been employed. The individual contributions of ionization prod ucts (N-2(2+)) and dissociation fragments (N+), which have both identical m ass-to-charge ratio and average velocity, are deduced from the analysis of product velocity distributions. Particular attention was paid to determinin g the transmission efficiency for dissociation fragments, since their colle ction was incomplete during the measurements. Threshold energies and kineti c energy released to dissociation fragments are measured. The role of state s contributing to different reactions is discussed. For DE, the present res ults are found to be much smaller than the results of Peterson et al (1998) . For ionization (single and dissociative), a satisfactory agreement with t heir result is obtained as well as with the prediction of Kim et al (2000) obtained in the binary-encounter Bethe approximation.