Rotational Excitation of Diatomic Molecules by Electron Impact

Abstract

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 $\ensuremath{\Delta}j\ensuremath{\ne}0$ transitions are independent of $s$-wave parameters, and ratios of $\ensuremath{\Delta}j=\ifmmode\pm\else\textpm\fi{}2$ cross sections agree with experimental results in ${\mathrm{H}}_{2}$ and with rotational close-coupling calculations. Absolute total and differential cross sections can be explained.