Consideration of L-Shell Ionization Cross Sections in Auger Electron Spectroscopy

Classical and quantum mechanical approaches to the LII,III-shell ionizations of isolated atoms by electron impact have been studied. Both descriptions are compared with new total ionization cross sections deduced from the LMM Auger spectra of chemisorbed monolayers. The LII,III-shell total ionization cross sections of S, Cl, Ti, and Cu adsorbed on metal surfaces are reasonably predicted by both theories at higher energies. A model for secondary excitation was recently developed to isolate the one-event cross section information. Calculations which include this effect lead to improved agreement between the experimental total ionization cross sections and those predicted by the single-event ionization theories.