Electron scattering by N₂ at 5 and 10 eV: Rotational-vibrational close-coupling calculations and crossed beam studies of vibrational excitation

The ratios of differential cross sections for excitation of the first excited vibrational state to differential cross sections for elastic scattering of N₂ have been measured at scattering angles ranging from 20° to 135° at 5 and 10 eV impact energies. Using previously measured and normalized elastic differential cross sections for N₂, the ratios have been converted to inelastic cross sections. Laboratory-frame close-coupling calculations using a four-state vibrational-rotational basis set and an effective interaction potential developed previously are reported at both energies. It is shown that the four-state treatment of this potential scattering model can account for the approximate magnitude and the qualitative behavior of the cross sections, but there are some significant quantitative differences between theory and experiment.