On the L3 level photoelectron spectrum of Cu metal measured in coincidence with the L3-VV Auger-electron spectrum

We provide an answer to the question why the L-3 photoelectron line of Cu metal measured in coincidence with the L-3-VV (F-3 or (1)G) Auger-electron line, does not line up with the L-3 single photoelectron line. We provide also an answer to the question why the L-3 coincidence photoelectron line is unshifted when the Auger-electron analyzer is moved away from the Auger-electron line. We show that it is the initial core-hole self-energy by the monopole excitation (screening) and the density of final states which play an important role in the shift and narrowing of Auger-photoelectron coincidence spectroscopy (APECS) spectral line. To explain the shifted APECS spectral line, Thurgate and Jiang (Surf. Sci. 466 (2000) L807) recently proposed the presence of two different core-hole states in the main-line state upon the L-3 level ionization in Cu metal. However, their explanation appears to be incorrect. (C) 2002 Elsevier Science B.V. All rights reserved.