Energy Spectra of Electrons from Autoionization States in Helium by Electron Impact

Abstract

Energy spectra of electrons ejected from autoionization states in helium excited by electron impact have been measured at bombarding energies from 65 to 250 eV as a function of the angle to the primary electron beam.The height of peaks of the energy spectra due to optically forbidden transitions from the ground state compared with those due to optically allowed transitions increases as the impact energy is reduced; this trend was most marked for the triplet-state $(2s2p)^{3}P$ excitation.