Spin-Resolved Collisions of Electrons with Rubidium Atoms: A Search for Relativistic Effects

The search for relativistic effects in electron-alkali scattering is currently a topic of considerable interest. The A2 spin asymmetry parameter is a direct measure of relativistic effects in the electron-atom collision process, as it is entirely dependent on the spin-orbit effect. We present measurements of the A2 spin asymmetry for the 5S 5P transition in rubidium at incident energies of 15, 20, 30 and 50 eV and for elastic scattering at 15, 20, 30, 50 and 80eV. Our results indicate that under these collision conditions, relativistic effects are measurable, in qualitative agreement with the available theory