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MO: Molekülphysik
MO 14: Femtosekundenspektroskopie V: molekulare Schwingungen
MO 14.5: Talk
Thursday, March 7, 2002, 15:00–15:15, HS 15/E07
A New Insight into the Control of Molecular Dynamics in Organometallic Molecules: Interpretation of the Optimized Pulse Shapes in the Light of sub-40 fs Pulses — •Štefan Vajda, Cosmin Lupulescu, Andrea Merli, and Ludger Wöste —
In this paper we characterize the ultrafast fragmentation and vibrational dynamics in electronically excited Fe(CO)2(NO)2 and CpMn(CO)3 by means of femtosecond time-resolved multi-photon ionization spectroscopy combined with mass spectrometry. From the transient two-colour multi-photon ionization data, it was possible to determine the lifetimes of parent molecule-ions and their photofragments. The experimentally observed decay times indicates an ultrafast loss of the first ligands taking place on the sub-100 fs time scale. Further we performed a feedback control experiment on the photofragmenting CpMn(CO)3 molecule in order to maximize the yield of a desired ionic product (parent molecule or a chosen intermediate) through pulse modulation. The shaped pulses obtained from optimization can be fully understood on the basis of our recently obtained high resolution pump-probe data exhibiting oscillatory behaviour. The timing of the pulse elements in the optimized pulse forms corresponds exactly the vibrations of electronically excited CpMn(CO)3 parent molecule. The fingerprints of the parent molecule vibrations are clearly resolved on the fragment transients and on the optimized pulse form obtained for the maximum ion yield of CpMn(CO)+.
[1]Š. Vajda, P. Rosendo-Francisco, C. Kaposta, M. Krenz, C. Lupulescu, and L. Wöste, Eur. Phys. J. D 16, 161 (2001)