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Photoelectron Imaging of Anions Illustrated by 310 Nm Detachment of F−
Published on: July 27, 2018
Threshold photoelectron spectroscopy of small organo-selenium radicals
Emil Karaev1, Dorothee Schaffner1, Marius Gerlach1
1University of Würzburg, Institute of Physical and Theoretical Chemistry, Am Hubland, 97074 Würzburg, Germany. ingo.fischer@uni-wuerzburg.de.
None:
We present threshold photoelectron spectra of several reactive selenium-containing intermediates generated by pyrolysis of dimethyldiselenide, (CH3)2Se2. The detected species include CH3Se2, Se2 and CH3Se radicals. Short-lived intermediates were produced in situ using a heated microreactor and characterized via mass-selected threshold photoelectron spectroscopy, using synchrotron radiation at the Swiss Light Source and a photoelectron-photoion coincidence (PEPICO) detection scheme. The data yield ionization energies for the transition into the ionic ground state of 8.28 eV ((CH3)Se2), 8.85 eV (Se2) and 8.92 eV ((CH3)Se). The values are accurate within ±10 to ±20 meV. In addition, transitions into excited electronic states of the ion were also investigated. Simulations of the vibrational structure based on quantum chemical calculations provide further insight into structural changes upon ionization. By directly comparing these results to previously studied sulfur and oxygen analogues, we identify both similarities and key differences in the bonding and fragmentation behavior of group 16 radicals.
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