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Double and Triple Ionisation of Isocyanic Acid
J H D Eland1, R J Squibb2, A J Sterling3
1Department of Chemistry, Physical and Theoretical Chemistry Laboratory, Oxford University, South Parks Road, Oxford, OX1 3QZ, United Kingdom.
Scientific Reports
|February 12, 2020
Summary
This study measured double and triple ionization spectra of isocyanic acid (HNCO) using advanced techniques. The research identified a stable doubly ionized HNCO state and determined its ionization energy, providing insights into molecular behavior.
Area of Science:
- Chemical Physics
- Atomic and Molecular Physics
- Quantum Chemistry
Background:
- Isocyanic acid (HNCO) is a reactive molecule with complex electronic structure.
- Understanding its ionization processes is crucial for various chemical and astrophysical applications.
- Previous studies have limited data on multiple ionization pathways of HNCO.
Purpose of the Study:
- To experimentally determine the double and triple ionization spectra of isocyanic acid (HNCO).
- To investigate the stability and electronic states of multiply charged HNCO ions.
- To compare experimental findings with theoretical calculations for validation and deeper understanding.
Main Methods:
- Multi-electron and ion coincidence spectroscopy.
- Synchrotron radiation as an ionization source.
- High-level theoretical electronic structure calculations.
Main Results:
- Measured the double and triple ionization spectra of HNCO.
- Identified a long-lived 3A" ground state for the doubly ionized HNCO molecule (HNCO2+) at 32.8 ± 0.3 eV.
- Determined the vertical triple ionization energy to be 65 ± 1 eV.
- Observed similarities between core-valence double ionization spectra and valence photoelectron spectra.
- Validated findings using a Coulomb model based on molecular orbital characteristics.
Conclusions:
- The study provides a comprehensive characterization of HNCO multiple ionization.
- The identified stable doubly ionized state has significant implications for understanding HNCO reactivity.
- The results offer valuable data for theoretical models and future studies on isocyanic acid and similar molecules.
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