Ultrafast Dynamics of Isolated Fluorenone

J. Kohler (1) , P. Hemberger (1) , I. Fischer (1) , G. Piani (2) , L. Poisson (2)

1 Institut fur Physikalische und Theoretische Chemie,
2 LFP - URA 2453 - Laboratoire Francis PERRIN

The ultrafast dynamics of isolated 9-fluorenone was studied by femtosecond time-resolved photoionization and photoelectron spectroscopy. The molecule was excited around 264-266 nm into the S6 state. The experimental results indicate that the excitation is followed by a multistep deactivation. A time constant of 50 fs or less corresponds to a fast redistribution of energy within the initially excited manifold of states, i.e., a motion away from the Franck-Condon region. Internal conversion to the S1 state then proceeds within 0.4 ps. The S1 state is long-lived, and only a lower bound of 20 ps can be derived. In addition, we computed excited state energies and oscillator strengths by TD-DFT theory, supporting the interpretation of the experimental data.

Domaines: Chimie théorique et/ou physique

J. Kohler, P. Hemberger, I. Fischer, G. Piani, L. Poisson. Ultrafast Dynamics of Isolated Fluorenone. Journal of Physical Chemistry A, 2011, 115 (50), pp.14249-14253. ⟨10.1021/jp2073649⟩. ⟨hal-00728736⟩