Work Group Prof. Dr. F. Temps

TOF-MS and photoelectron imaging

Femtosecond time-resolved ion yield spectroscopy (fs-IYS) and photoelectron imaging spectroscopy (fs-PEIS) in combination are probably the most powerful tools to probe the ultrafast dynamics of molecules in excited electronic states. 

Hexafluorobenzene
Coherent  oscillation  due to an  out-of-plane  vibrational motion in the femtosecond
ion yield spectrum of hexafluorobenzene (HFB) after femtosecond laser excitation
to the ππ* state at λ = 260 nm.                                      (c) H. Studzinski, F. Temps

   

Femtosecond time-resolved PEIS, in particular, allows one to follow ultrafast radiationless transitions in a photo-excited molecule from the initial optically bright state to lower-lying optically dark states, which cannot easily be identified by other means. We apply this method to idealized model compounds to elucidate basic photo-induced dynamics in organic chromophores. Interesting examples are hexa- and pentafluorobenzene, model compounds for DNA bases, diazocine, and sunscreen molecules.

Important papers:

  • H. Studzinski, S. Zhang, Y. Wang, F. Temps, "Ultrafast Non-Radiative Dynamics in Electronically Excited Hexafluorobenzene by Femtosecond Time-Resolved Mass Spectrometry", J. Chem. Phys. 128, 164314 (2008).  
    DOI: 10.1063/1.2907859