Berlin 2014 – scientific programme
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SYPS: Promovierendensymposium
SYPS 1: Velocity map imaging - focusing on intra- and interatomic dynamics 1
SYPS 1.3: Talk
Thursday, March 20, 2014, 15:10–15:25, Audimax
Insight in chemical dynamics by three-dimensional momentum imaging — •Robert Siemering1, Eric Wells2, Itzik Ben-Itzhak3, Matthias Kling4, and Regina de Vivie-Riedle1 — 1Ludwig-Maximilians-Universität, München, Germany — 2Augustana College, Sioux Falls, USA — 3Kansas State University, Manhattan, USA — 4Max Planck Institute of Quantum Optics, Garching, Germany
The description of laser pulse interaction with molecules have different constrains for theory and experiment. While adaptive feedback in experiments can manipulate dynamics in molecular systems, the finding of the underlying mechanism or the forming of an appropriate theoretical model is difficult. This is especially the case when the feedback is limited to a single observable. By rapidly inverting velocity map images of ions to recover the three-dimensional photofragment momentum distribution and incorporating that feedback into the control loop, the specificity of the control objective is dramatically increased. As an example in the isomerization of acetylene (C2H22+ → CH2+ + C+) the angle-resolved ratio of CH+/CH2+ was controlled in the experiment[1]. With the experimentally obtained pulses on-the-fly-trajectories were performed to unveils the underlying barrier suppression mechanism. The theoretical model can explain the observed shift to lower kinetic energy release values for the CH2+ fragments.
[1] Wells, E., et al., Adaptive Strong-field Control of Chemical Dynamics Guided by Three-dimensional Momentum Imaging, Nature Communications, DOI:10.1038/ncomms3895