Angle-resolved Auger spectra of the molecule

Abstract

Auger decay spectra of the ethyne (acetylene) molecule have been measured at photon energies below as well as above the C 1s ionization threshold. Angular anisotropy has been observed at the π * resonance and in the region of a continuum feature previously assigned to a σ * resonance, but disappears far above threshold. Because of strong configuration interaction in the final state only high kinetic energy Auger transitions can be assigned to individual electronic states. In the case of resonant Auger decay, this mixing of states also blurs the division of the spectrum into participator and spectator features. Decay spectra resonances assist in the assignment of Rydberg resonances. The decay of the double excitations above the C 1s threshold has also been studied.

Molecular Inner‐Shell Spectroscopy. ARPIS Technique and its Applications

“…The and symmetries are resolved completely in C 2 H 2 , as well as in N 2 and CO, except for the lowest absorption feature with a term value (T) of 2.8-3.4 eV. Some groups [93,94] assigned the 1s→ 3sσ g and 3pσ u Rydberg excited states to the lowest feature with T = 2.8-3.4 eV. However, both the 1s → 3pσ u and 3pπ u Rydberg transitions with T = 2.5 eV are clearly resolved as strong peaks, whereas the npσ Rydberg series is weak in N 2 and CO.…”

Electron spectroscopies and inelastic processes in nanoclusters and solids: Theory and experiment

“…The core-excited spectrum of C 2 H 2 is dominated by the C 1σ u −→ 1π g transition at 285.8 eV photon energy as seen in Fig. 30 (see [222]). The process under investigation is…”

“…spectrum includes neither vibrational structures (not even resolved in the experimental spectrum by Kivimäki et al [222]), nor the broadening and profile deformation of the spectral lines due to vibrational transitions. Comparison with the experimental spectrum requires one to account for the characteristics of both the incident radiation, almost perfectly polarized alongẑ, but having a finite dispersion ( 0.6 eV in Kivimäki's experiment) around the exciting frequency and the finite energy resolution of the electron spectrometer: as by Eq.…”

“…30. The absolute photoabsorption spectrum of C 2 H 2 at the C 1s edge [222]. Source: Reprinted from [222] with kind permission of the Institute of Physics.…”

“…The absolute photoabsorption spectrum of C 2 H 2 at the C 1s edge [222]. Source: Reprinted from [222] with kind permission of the Institute of Physics. Taioli and coworkers [214] studied the decay state of the molecule dividing the spectrum into spectator and participator features.…”