Ultrafast dynamics of isolated phenylcarbenes followed by femtosecond time-resolved velocity map imaging

B. Noller (1, 2) , L. Poisson (1) , R. Maksimenka (1) , O. Gobert (3) , I. Fischer (2) , J.-M. Mestdagh (1)

1 LFP - URA 2453 - Laboratoire Francis PERRIN
2 Institut of Physical Chemistry
3 SPAM - Service des Photons, Atomes et Molécules

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 1A′ state, corresponding to excitation from a π-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 36000 cm−1 and 41000 cm−1 range and gives rise to very similar dynamics, although it has a triplet ground state. The experimental data were augmented by computations.

Domaines: Chimie théorique et/ou physique

B. Noller, L. Poisson, R. Maksimenka, O. Gobert, I. Fischer, et al.. Ultrafast dynamics of isolated phenylcarbenes followed by femtosecond time-resolved velocity map imaging. Journal of Physical Chemistry A, 2009, 113 (13), pp.3041-3050. ⟨10.1021/jp810974m⟩. ⟨hal-00420314⟩