Relating the 4sσ-1 inner-valence photoelectron spectrum of HBr with the Br 3d-15lλ resonant Auger spectra: An approach to the assignments

The high resolution Br 4sσ-1 photoelectron spectrum of HBr is presented together with the resonant Auger spectra resulting from excitations from the 3d core levels to the low-n Rydberg orbitals 5sσ, 5pσ, and 5pπ. The very complex spectra can be broadly assigned using two observations. First, the energy splittings of the 4pπ-25s and 4pπ-25p states are very similar to the splittings of the 4pπ-2(1Σ+,1Δ, and 3Σ-) final states seen previously in the normal Auger spectra. Second, the 2Σ+ states, which are the dominant correlation satellites in the complex 4sσ-1 photoelectron spectrum, are often enhanced in the 5sσ resonance Auger spectra. Electron correlation and spin-orbit interaction in the final states are important to understand all of these spectra. Unlike the normal Auger spectra, vibrational excitations play only a minor role in these spectra, showing that the 5s and 5p Rydberg orbitals have some bonding character