title: Photoionisation of the tropyl radical.
abstract: We present a study on the photoionisation of the cycloheptatrienyl (tropyl) radical, C7H7, using tunable vacuum ultraviolet synchrotron radiation. Tropyl is generated by flash pyrolysis from bitropyl. Ions and electrons are detected in coincidence, permitting us to record mass-selected photoelectron spectra. The threshold photoelectron spectrum of tropyl, corresponding to the X (+ 1)A1' ← X (2)E2" transition, reveals an ionisation energy of 6.23 ± 0.02 eV, in good agreement with Rydberg extrapolations, but slightly lower than the value derived from earlier photoelectron spectra. Several vibrations can be resolved and are reassigned to the C-C stretch mode ν16 (+) and to a combination of ν16 (+) with the ring breathing mode ν2 (+). Above 10.55 eV dissociative photoionisation of tropyl is observed, leading to the formation of C5H5 (+) and C2H2.
authors.affiliation: Institute of Physical and Theoretical Chemistry, University of Würzburg, Am Hubland Süd, 97074 Würzburg, Germany.
authors.forename: Kathrin H
authors.initials: KH
authors.lastname: Fischer
authors.forename: Patrick
authors.initials: P
authors.lastname: Hemberger
authors.forename: Andras
authors.initials: A
authors.lastname: Bodi
authors.forename: Ingo
authors.initials: I
authors.lastname: Fischer
keywords: dissociative photoionisation; gas phase; reactive intermediates; synchrotron radiation; threshold photoelectron spectroscopy