Scattering of Low-Energy Electrons by Excited Sodium Atoms Using a Photon and Electron Atomic Beam Recoil Technique

A new method for measuring cross sections for the scattering of electrons by laser-excited atoms is described. It is a generalization of the atomic-beam recoil technique, taking advantage of the recoil of atoms during resonant photon interactions to spatially separate excited from nonexcited atoms. A preliminary value for the total cross section for the scattering of electrons by the $3{}_{}{}^2{}_{}{}^{}P_{\frac{3}{2}}^{}{}_{}{}^{}(m_F=3)$ state of sodium at 4.4 eV is presented.