Rotational Excitation of Diatomic Molecules by Electron Impact

Rotational excitation of homonuclear diatomic molecules can be simply yet accurately calculated from the scattering parameters of elastic electron-molecule scattering in the fixed-nuclei approximation. The total scattering cross sections for Δj≠0 transitions are independent of s-wave parameters, and ratios of Δj=±2 cross sections agree with experimental results in H₂ and with rotational close-coupling calculations. Absolute total and differential cross sections can be explained.