Auger decay of the C 1s−12π* resonance in carbon monoxide: Vibrationally and angularly resolved spectra

Abstract

Auger electron spectra from the decay of the ν=0, 1, and 2 levels of the C 1s−12π* state were measured with sufficiently high electron and photon energy resolution to completely resolve the vibrational structure of the final electronic states. The results are compared with ab initio calculations with emphasis on the analysis of the spectator Auger transitions. The anisotropy parameters extracted from angle-resolved spectra show variations within the vibrational envelopes of the participator Auger decay and exhibit a complex oscillating behavior for the spectator Auger transitions. In addition, two-dimensional (2D) imaging of the electron emission across the C 1s−12π* resonance was performed. The ratio of resonant and nonresonant ionization processes is estimated from the 2D map. Strong vibrational lifetime interference effects apparent in the 2D imaging are discussed.