title: Ultrafast dynamics of isolated phenylcarbenes followed by femtosecond time-resolved velocity map imaging.
abstract: The ultrafast dynamics of two carbene model systems, chlorophenylcarbene (CPC) and trifluoromethylphenylcarbene (TFPC), has been studied in a molecular beam. Velocity map imaging aids optimizing the pyrolysis conditions for a clean generation of reactive intermediates by supersonic jet flash pyrolysis. The dynamics was followed in real time by time-resolved mass spectroscopy and photoion and photoelectron imaging. CPC was excited at 265 nm into the 3 (1)A' state, corresponding to excitation from a pi-orbital of the aromatic ring into the lowest unoccupied molecular orbital, which contains the p-orbital at the carbene center. The experimental results suggest a three step deactivation process in agreement with computations. TFPC exhibits two absorption bands in the 36,000 cm(-1) and 41,000 cm(-1) range and gives rise to very similar dynamics, although it has a triplet ground state. The experimental data were augmented by computations.
authors.affiliation: Laboratoire Francis Perrin, CNRS URA 2453, CEA IRAMIS/Service des Photons, Atoms et Molecules, F-91191 Gif-sur-Yvette Cedex, France.
authors.forename: Bastian
authors.initials: B
authors.lastname: Noller
authors.forename: Lionel
authors.initials: L
authors.lastname: Poisson
authors.forename: Raman
authors.initials: R
authors.lastname: Maksimenka
authors.forename: Oliver
authors.initials: O
authors.lastname: Gobert
authors.forename: Ingo
authors.initials: I
authors.lastname: Fischer
authors.forename: J M
authors.initials: JM
authors.lastname: Mestdagh