Many-body calculation of the coincidence L3 photoelectron spectroscopy main line of Ni metal

The partial singles L3 photoelectron spectroscopy (PES) main line of Ni metal correlated with Auger electrons emitted by the localized L3-VV Auger decay is calculated by a many-body theory. The partial singles L3 PES main line of Ni metal almost coincides in both line shape and peak kinetic energy (KE) with the singles one. The former main line peak shows a KE shift of only 0.01 eV toward the lower KE and a very small asymmetric line shape change compared to the singles one. The asymmetric line shape change and the peak KE shift of the partial singles L3 main line are very small. However, they are due to the variation with photoelectron KE in the branching ratio of the partial Auger decay width in the partial singles L3 PES main line by the photoelectron KE dependent imaginary part of the shakeup self-energy. The L3 PES main line of Ni metal measured in coincidence with the L3-VV (1G) Auger electron spectroscopy (AES) main line peak is the partial singles one modulated by a spectral function Ra of a fixed energy Auger electron analyzer so that it should show only a symmetric line narrowing by Ra compared to the singles one. The L3 PES main line peak of Ni metal measured in coincidence with the delocalized band-like L3-VV AES peak or not completely split-off (or not completely localized) L3-VV (3F) AES peak, will show an asymmetric line narrowing and a KE shift compared to the singles one. Thus, the L3 PES main line of Ni metal in coincidence with various parts of the L3-VV AES spectrum depends on which part of the L3-VV AES spectrum a fixed energy Auger electron analyzer is set. The experimental verification is in need.