Surface electronic structure and off-site Auger transitions on TaC(111) observed with Auger-photoelectron coincidence spectroscopy

The LVV Auger line shape of sulfur on copper studied by Auger photoelectron coincidence spectroscopy

We have studied the line shapes of Cu(0 0 1)-p (2 × 2)S L2VV and L3VV Auger decay by means of Auger photoelectron coincidence spectroscopy. Measuring the LVV Auger spectrum in coincidence with S 2p1/2 and 2p3/2 photoelectrons respectively, we have been able to separate the two overlapping Auger spectra and determine their intrinsic line shapes. The two Auger transitions, though shifted in energy, display an identical line shape whose main features can be qualitatively understood considering a single particle approximation but are better described within a Cini-Sawatzky (CS) approach. Comparison between the experimental and the CS calculated spectra confirms that a substantial part of the Auger lines (∼20%) can be ascribed to decay events accompanied by the excitation of one additional electron-hole pair in the valence band. For the first time, the locality of the Auger process combined with the surface sensitivity of the APECS technique and its ability to separate overlapping structures are used to study Auger transitions taking place at the the surface states of a S/noble-metal interface.

Radiationless decay in the region of the 2t2g and 4eg resonances in SF6

The S 2p Auger spectrum of SF(6) has been studied in the region of the 2t(2g) and 4e(g) resonances. The partial Auger spectra due to the ionization of the 2p spin-orbit components and of a shake-up satellite state have been measured selectively by tuning the photon energy and using the Auger electron-photoelectron coincidence technique. A detailed analysis of the Auger spectrum has also been performed using the Green's function-based second-order algebraic diagrammatic construction method.

The OCS S L3MM auger spectrum and angular distributions studied by photoelectron-auger electron coincidence experiments

The selectivity of the photoelectron-Auger electron coincidence technique has been used to isolate the S L(3)MM contribution to the L(2,3)MM Auger spectrum in OCS. In this way, a direct comparison of the energies, widths, and relative intensities of the final OCS(2+) states with theoretical calculations has been achieved. Moreover, the angular distributions of some selected Auger electrons have been measured in coincidence with the photoelectron at two different photon energies. In contrast with the results of noncoincidence measurements, the coincidence angular distributions show a significant asymmetry and a dependence on the photon energy and OCS(2+) final state.