On the L 3 level photoelectron spectrum of Cu metal measured in coincidence with the L 3–VV Auger-electron spectrum

Abstract

We provide an answer to the question why the L 3 photoelectron line of Cu metal measured in coincidence with the L 3–VV ( 3F or 1G) 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.