TY  - JOUR
A1  - Reusch, Engelbert
A1  - Holzmeier, Fabian
A1  - Gerlach, Marius
A1  - Fischer, Ingo
A1  - Hemberger, Patrick
T1  - Decomposition of Picolyl Radicals at High Temperature: A Mass Selective Threshold Photoelectron Spectroscopy Study
JF  - Chemistry - A European Journal
N2  - The reaction products of the picolyl radicals at high temperature were characterized by mass‐selective threshold photoelectron spectroscopy in the gas phase. Aminomethylpyridines were pyrolyzed to initially produce picolyl radicals (m /z =92). At higher temperatures further thermal reaction products are generated in the pyrolysis reactor. All compounds were identified by mass‐selected threshold photoelectron spectroscopy and several hitherto unexplored reactive molecules were characterized. The mechanism for several dissociation pathways was outlined in computations. The spectrum of m /z =91, resulting from hydrogen loss of picolyl, shows four isomers, two ethynyl pyrroles with adiabatic ionization energies (IE\(_{ad}\)) of 7.99 eV (2‐ethynyl‐1H ‐pyrrole) and 8.12 eV (3‐ethynyl‐1H ‐pyrrole), and two cyclopentadiene carbonitriles with IE′s of 9.14 eV (cyclopenta‐1,3‐diene‐1‐carbonitrile) and 9.25 eV (cyclopenta‐1,4‐diene‐1‐carbonitrile). A second consecutive hydrogen loss forms the cyanocyclopentadienyl radical with IE′s of 9.07 eV (T\(_0\)) and 9.21 eV (S\(_1\)). This compound dissociates further to acetylene and the cyanopropynyl radical (IE=9.35 eV). Furthermore, the cyclopentadienyl radical, penta‐1,3‐diyne, cyclopentadiene and propargyl were identified in the spectra. Computations indicate that dissociation of picolyl proceeds initially via a resonance‐stabilized seven‐membered ring.
KW  - ionization energy
KW  - photoelectron spectroscopy
KW  - pyrolysis
KW  - radicals
KW  - synchrotron radiation
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-208132
VL  - 25
IS  - 72
ER  - 
TY  - JOUR
A1  - Schleier, Domenik
A1  - Reusch, Engelbert
A1  - Lummel, Lisa
A1  - Hemberger, Patrick
A1  - Fischer, Ingo
T1  - Threshold photoelectron spectroscopy of IO and IOH
JF  - ChemPhysChem
N2  - Iodine oxides appear as reactive intermediates in atmospheric chemistry. Here, we investigate IO and HOI by mass‐selective threshold photoelectron spectroscopy (ms‐TPES), using synchrotron radiation. IO and HOI are generated by photolyzing iodine in the presence of ozone. For both molecules, accurate ionization energies are determined, 9.71±0.02 eV for IO and 9.79±0.02 eV for HOI. The strong spin‐spin interaction in the 3Σ− ground state of IO+ leads to an energy splitting into the Ω=0 and Ω=±1 sublevels. Upon ionization, the I−O bond shortens significantly in both molecules; thus, a vibrational progression, assigned to the I−O stretch, is apparent in both spectra.
KW  - ionization potential
KW  - radicals
KW  - reactive intermediates
KW  - photolysis
KW  - synchrotron radiatoren
Y1  - 2019
U6  - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204751
VL  - 20
IS  - 19
ER  -