Hannover 2016 – scientific programme

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MO: Fachverband Molekülphysik

MO 19: Posters 4: Novelties in Molecular Physics: Femtosecond Spectroscopy, Molecular Clusters, Cold Molecules and Helium Droplets

MO 19.7: Poster

Thursday, March 3, 2016, 16:30–19:00, Empore Lichthof

Ultrafast Ionization and Fragmentation Dynamics of Chlorinated Silane Derivatives — •Ina Halfpap, Clara Adele von Randow, Egill Antonsson, Christopher Raschpichler, and Eckart Rühl — Physical Chemistry, Freie Universität Berlin, Takustr. 3, 14195 Berlin

The femtosecond pump-probe technique is known to be a suitable approach to study molecular strong-field ionization processes in the time domain. To follow specific fragmentation pathways, mass spectrometry is the most suitable approach. The fragmentation dynamics of highly excited molecular neutrals and ions can be affected by dynamic resonances, where the wavepacket motion on ionic potential energy surfaces plays a crucial role.

We present recent results on the ionization and fragmentation dynamics of trichloromethylsilane (SiCl₃CH₃), dichlorodimethylsilane (SiCl₂(CH₃)₂), and chloro-trimethylsilane (SiCl(CH₃)₃) investigated by a one-color 804 nm femtosecond pump-probe experiment recording the ion yields of fragment ions. The intense pump pulse (250 µJ/pulse) is used to ionize the sample molecules which is followed by a time delayed less intense probe pulse (70 µJ/pulse). This leads to additional fragmentation of the parent and fragment ions. The yields of parent and fragment ions show broad dynamic resonances with maxima in a range of Δt = 0.5 ps. The experimental findings are explained in terms of dynamic ionic resonances leading to an enhanced dissociation of the parent ions as well as some fragment ions.