Superelastic electron scattering from laser excited rubidium at 20 eV incident energy

Superelastic electron scattering measurements are presented from rubidium atoms excited by laser radiation to the 5(2)p states at around 780 nm. The incident energy of the electrons was 18.4 eV corresponding to 20 eV incident electrons for the excitation process 5(2)S-5(2)P. The measurements were conducted over a range of scattering angles from 5degrees through to 125degrees. A complete set of atomic collision parameters for the interaction process is presented together with the associated pseudo-Stokes parameters obtained from the measurements. A comparison with three sophisticated theoretical models indicates that none of the models completely describes the interaction process at this energy, and that further experimental and theoretical work is needed.