Origin of enhanced vibrational excitation inN2by electron impact in the 15-35 eV region

The authors calculate the integrated vibrational excitation cross section for $e$-${\mathrm{N}}_2$ scattering in the interval 0-50 eV using the continuum multiple-scattering model with the Hara exchange approximation. Resonant enhancement is observed at 2.4 eV owing to the well-known ${\pi }_g$ shape resonance. In addition, however, enhanced vibrational excitation is found centered at ∼26 eV, arising from a broad shape resonance in the ${\sigma }_u$ channel. The authors propose this one-electron feature as the main source of the enhanced vibrational excitation observed by Pavlovic et al. in the 15-35 eV region.