Vibrational Excitation in CO by Electron Impact in the Energy Range 10-90 eV

The ratio of the scattering intensity for the v^''=1 excitation to the elastic scattering intensity at 40^∘{} and 80^∘{} scattering angles has been determined for 10-90-eV impact energies for electron scattering by CO. These ratio curves exhibit broad peaks near 20-eV impact energy which cannot be accounted for by plane-wave calculations based on potential scattering models. The peaks are indicative of a resonant excitation process (or processes) in the v^''=1 channel in the range 15-25 eV.