Role of the Born-Oppenheimer approximation in the vibrational excitation of molecules by electrons

The role of the Born-Oppenheimer approximation in the resonant vibrational excitation of diatomic molecules by electrons is reexamined in the light of a recent paper on the hybrid theory and calculation of $e+{\mathrm{N}}_2$ scattering by Chandra and Temkin. It is pointed out that it is not necessary to resort to a nonadiabatic vibrational close-coupling expansion to reproduce the substructure seen in the resonant vibrational excitation cross section of ${\mathrm{N}}_2$ by electrons. Finally, comment is made on the reasons for the slow convergence of the vibrational close-coupling treatment from a compound-state point of view of the scattering process.