Angular distributions in the electron impact excitation of Xe at 20 eV

Electron impact energy-loss spectra of Xe have been studied at 20 eV incident electron energy from 5° to 135° scattering angle. Differential and integral cross sections for elastic scattering and for the excitation of electronic states up to 10.60 eV energy loss have been determined. The validity of the optical selection rules and the previously established angular behavior associated with direct and exchange processes were examined for this intermediate coupling case.