Normal and resonant Auger spectroscopy of isocyanic acid, HNCO

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In this paper, we investigate HNCO by resonant and nonresonant Auger electron spectroscopy at the K-edges of carbon, nitrogen, and oxygen, employing soft X-ray synchrotron radiation. In comparison with the isosteric but linear CO2 molecule, spectra of the bent HNCO molecule are similar but more complex due to its reduced symmetry, wherein the degeneracy of the π-orbitals is lifted. Resonant Auger electron spectra are presented at different photon energies over the first core-excited 1s → 10a′ resonance. All Auger electron spectra are assigned based on ab initio configuration interaction computations combined with the one-center approximation for Auger intensities and moment theory to consider vibrational motion. The calculated spectra were scaled by a newly introduced energy scaling factor, and generally, good agreement is found between experiment and theory for normal as well as resonant Auger electron spectra. A comparison of resonant Auger spectra with nonresonant Auger structures shows a slight broadening as well as a shift of the former spectra between -8 and -9 eV due to the spectating electron. Since HNCO is a small molecule and contains the four most abundant atoms of organic molecules, the reported Auger electron decay spectra will provide a benchmark for further theoretical approaches in the computation of core electron spectra.


  • F. Holzmeier
  • T. J.A. Wolf
  • C. Gienger
  • I. Wagner
  • J. Bozek
  • S. Nandi
  • C. Nicolas
  • I. Fischer
  • M. Gühr
  • R. F. Fink
External organisations
  • University of Paris-Sud
  • Synchrotron SOLEIL
  • Stanford Linear Accelerator Center (SLAC)
  • University of Tübingen
  • Julius Maximilian University of Würzburg
  • University of Potsdam
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Atom and Molecular Physics and Optics
Original languageEnglish
Article number034308
JournalJournal of Chemical Physics
Issue number3
Publication statusPublished - 2018 Jul 21
Publication categoryResearch