Measurement of the collision-induced alignment in the differential scattering by laser-excited atoms: 3P to nS transitions excited by electron scattering on sodium

Abstract
Electron scattering by excited sodium atoms has been carried out in a crossed-beam experiment. The atoms have been optically pumped into a well defined hyperfine level (32P32/F=3) by a tunable CW dye laser. For two of the most prominent scattering processes, the 32P to 32S and 32P to 42S transitions, the effect of the anisotropy of the initial state introduced by the laser light is studied in detail and is interpreted in terms of multipole moments describing the optical excitation and the collision process. Possibilities and limitations of the experiment are discussed. Electron collisions may be seen as a test case for the understanding of more involved interaction processes.