Core-electron excitations and the electronic decay of core-to-bound-state transitions in condensed azabenzenes

Abstract

We have measured N 1s near edge absorption spectra and the kinetic energy distribution of electrons emitted in the decay of N 1s core-to-bound-state excitations in condensed pyridine, pyrazine, and s-triazine. The electron emission spectra generated in the electronic decay of the core to bound state resonances lead to singly charged, participator-type molecular final states, equivalent to the final states populated in photoemission, as well as to double hole (Auger) spectator-type final states screened by the presence of a π spectator electron. The deexcitation spectra, therefore, give insight into charge–transfer and screening processes in the initial core-electron excited state, as well as in the final spectator double-hole states. One of the most prominent participator features observed in the spectra of pyridine, pyrazine, and s-triazine is due to the emission of the most strongly bound π electrons, reflecting the dynamic screening of the core hole in the aromatic azabenzene molecules. The spectator states, on the other hand, exhibit a much reduced screening energy shift compared to linear molecules due to the delocalized nature of the π spectator electron.