Threshold photoelectron spectroscopy of unstable N-containing compounds: Resolution of ΔK subbands in HNCO{sup +} and vibrational resolution in NCO{sup +}

Journal Article · Thu May 14 04:00:00 EDT 2015 · Journal of Chemical Physics

DOI:https://doi.org/10.1063/1.4920951· OSTI ID:22415769

Holzmeier, Fabian; Lang, Melanie; Fischer, Ingo ^[1]; Tang, Xiaofeng ^[2]; Cunha de Miranda, Barbara; Romanzin, Claire; Alcaraz, Christian ^[3]; Hemberger, Patrick ^[4]

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1. Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland, D-97074 Würzburg (Germany)
2. Synchrotron SOLEIL, l’Orme des Merisiers, Saint Aubin BP 48, F-91192 Gif sur Yvette Cedex (France)
3. Laboratoire de Chimie-Physique, UMR 8000 CNRS and Université Paris-Sud 11, F-91405 Orsay Cedex (France)
4. Molecular Dynamics Group, Paul Scherrer Institute (PSI), CH-5232 Villigen (Switzerland)

The threshold photoelectron spectra (TPES) of two unstable nitrogen-containing species, HNCO and NCO, were recorded utilizing vacuum ultraviolet synchrotron radiation. Both are intermediates in combustion processes and play a role in the removal of nitrogen oxides from exhaust gases. The rovibronic structure of the first band in the TPES of HNCO{sup +} was analyzed within the framework of an orbital ionization model, and the resolved structure of the origin band was assigned to ΔK subbands. An ionization energy of 11.602 ± 0.005 eV was determined and the vibrational structure of the cationic ground state was analyzed by a Franck-Condon fit. Low lying electronically excited states of HNCO{sup +} were also observed. In a second series of experiments, the NCO radical was generated by flash pyrolysis from chlorine isocyanate. The ionization energy to the X{sup +} {sup 3}Σ{sup −} ground state was determined to be 11.76 ± 0.02 eV, while for the a{sup +1}Δ state, a value of 12.93 ± 0.02 eV was obtained. Vibrational structure was observed for both states, and bands were assigned by Franck-Condon simulations.

• OSTI ID: 22415769
• Journal Information: Journal of Chemical Physics, Journal Name: Journal of Chemical Physics Journal Issue: 18 Vol. 142; ISSN JCPSA6; ISSN 0021-9606
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
74 ATOMIC AND MOLECULAR PHYSICS
CHLORINE
COMPUTERIZED SIMULATION
EV RANGE
EXCITED STATES
EXHAUST GASES
FRANCK-CONDON PRINCIPLE
GROUND STATES
ISOCYANATES
NITROGEN OXIDES
PHOTOELECTRON SPECTROSCOPY
PYROLYSIS
RADICALS
RESOLUTION
SYNCHROTRON RADIATION
ULTRAVIOLET RADIATION