Resonant Auger decay induced by the symmetry-forbidden 1a1g → 6a1g transition of the SF6 molecule

Resonant Auger electron spectroscopic study at the symmetry-forbidden 1 a 1 g → 6 a 1 g excitation below the S K-shell threshold of SF 6 is reported. Partial electron yield and resonant K L L Auger spectra have been measured by using monochromatized undulator synchrotron radiation. By changing the p...

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Bibliographic Details
Published in:Journal of vacuum science & technology. A, Vacuum, surfaces, and films Vacuum, surfaces, and films, 2022-07, Vol.40 (4)
Main Authors: Santos, A. C. F., Travnikova, O., Boudjemia, N., Marchenko, T., Guillemin, R., Ismail, I., Koulentianos, D., Céolin, D., Gel’mukhanov, F., Simon, M., Piancastelli, M. N., Püttner, R.
Format: Article
Language:English
Subjects:
Chemical Physics
Physics
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Summary:Resonant Auger electron spectroscopic study at the symmetry-forbidden 1 a 1 g → 6 a 1 g excitation below the S K-shell threshold of SF 6 is reported. Partial electron yield and resonant K L L Auger spectra have been measured by using monochromatized undulator synchrotron radiation. By changing the photon energy in small steps, a so-called 2D map is produced. In this map, the dipole-forbidden transition exhibits spectral features (e.g., an S-shaped dispersion relation), which are well known and understood for dipole-allowed transitions. We validate by a theory that for the case of dipole-forbidden transitions, these spectral features can be analyzed in the same way as previously established for the dipole-allowed ones. This approach grants information on the nuclear dynamics in the K-shell core-excited states of SF 6 on the femtosecond (fs) timescale. In particular, for the potential-energy curves of the states S 1 s − 1 6 a 1 g and S 2 p − 2 6 a 1 g, the slopes at the equilibrium distance of the ground state are derived. Symmetry breaking as a result of ultrafast vibronic coupling is revealed by the population of the electronically forbidden excited state.
ISSN:0734-2101
1520-8559
DOI:10.1116/6.0001890