Cross sections, polarization and orientation in electron-impact excitation to states

This work reports results from a comprehensive experimental and theoretical study of the electron-impact excitation of some levels belonging to the configuration in neon. We performed electron-polarized photon coincidence experiments for the excitation of the and levels in neon where the polarized photon emitted in the radiative decay was detected in coincidence with the scattered electron. We report experimental results for the Stokes parameters (i = 1,2,3,4), for an incident electron energy of in the electron scattering angular range of -, and for for the angle of , thus supplementing results reported earlier for this energy for the angular range -. We also report here theoretical distorted-wave approximation (DWA) and first-order many-body theory (FOMBT) results for the same excitations and electron energies for the integral cross sections (ICSs), for differential cross sections (DCSs), and for Stokes parameters. Our theoretical results are compared with all available experimental results. A detailed discussion and some conclusions with respect to the physics involved in the excitation processes considered here are then presented. We also give a theoretical discussion about the nature of the information that can be obtained about the collision process by analysing the experimental data. In particular, in this study we found both experimentally and numerically that the angular momentum transferred to the target, , as a function of electron scattering angle is the same, within experimental error, for the states with total angular momentum J = 2.