The x-ray absorption spectrum of the propargyl radical C3H3●
Abstract
We report a combined experimental and computational study of the near-edge X-ray absorption fine structure (NEXAFS) spectrum of the propargyl radical, C3H3●. As a central intermediate in the formation of polycyclic aromatic hydrocarbons, the propargyl radical is a species of considerable relevance in combustion and astrochemistry and was here generated by pyrolysis from propargyl bromide. The NEXAFS spectrum shows a pronounced band at 282.2 eV corresponding to transitions from carbon 1s orbitals to singly occupied molecular orbitals. Ab initio calculations reveal that two transitions to the lowest-lying states 1 A12 and 2 A12, which take place from the C1s orbital of the two terminal carbon atoms, contribute to this band. In addition, a 420 meV spacing of the first band is visible and is assigned to a vibrational progression in the symmetric CH2 stretch. Transitions at higher energies are also described reasonably well by theory. The fragmentation pattern was investigated at the different resonant transitions and shows the cleavage of one as well as both C–C bonds.
Article Details
Journal Info
The Journal of Chemical Physics
American Institute of Physics
Authors (11)
Dorothee Schaffner
Institute of Physical and Theoretical Chemistry, University of Würzburg 1 , D-97074 Würzburg,
Theo Juncker von Buchwald
DTU Chemistry, Technical University of Denmark 2 , DK-2800 Kgs. Lyngby,
Jacob Pedersen
Department of Chemistry
Andreas Rasp
Institute of Physical and Theoretical Chemistry, University of Würzburg 1 , D-97074 Würzburg,
Emil Karaev
Institute of Physical and Theoretical Chemistry, University of Würzburg 1 , D-97074 Würzburg,
Valentin von Laffert
Institute of Physical and Theoretical Chemistry, University of Würzburg 1 , D-97074 Würzburg,
Alessio Bruno
Dipartimento di Chimica e Tecnologia dei Farmaci, Università degli Studi di Roma “La Sapienza” 4 , piazzale Aldo Moro 5, I-00185 Rome,
Michele Alagia
CNR - Istituto Officina dei Materiali (IOM), Laboratorio TASC 5 , I-34149 Trieste,
Stefano Stranges
Dipartimento di Chimica e Tecnologia dei Farmaci, Università degli Studi di Roma “La Sapienza” 4 , piazzale Aldo Moro 5, I-00185 Rome,
Ingo Fischer
Institute of Physical and Theoretical Chemistry, University of Würzburg 1 , D-97074 Würzburg,
Sonia Coriani
Department of Chemistry