Auger spectra of thiouracils: Three molecules and four edges

This study presents a comprehensive investigation of the Auger spectra of three thionated uracils using a combination of theory and experiment. Non-resonant Auger spectra measured at the K-edges of carbon, nitrogen, and oxygen, as well as at the L2,3 edge of sulfur, are reported. Even though the final decay states (valence two-hole states) are the same for all edges, the resulting Auger spectra are strikingly different, highlighting the local nature of the Auger decay. Theoretical modeling, which employed a series of approaches incorporating varying levels of correlation and different treatments of the metastable states, provides a clear interpretation of the experimental spectra. The analysis highlights the crucial role of electron correlation, evident in both the density of the decay states and the spectra constructed using channel-specific partial decay widths, as well as the importance of spin–orbit coupling in shaping the L-edge spectra of thiouracils.