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Published on: July 27, 2018
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Disentangling Multichannel Photodissociation Dynamics in Acetone by Time-Resolved Photoelectron-Photoion Coincidence
Paul Maierhofer1, Markus Bainschab1, Bernhard Thaler1
1Institute of Experimental Physics, Graz University of Technology, NAWI Graz , Petersgasse 16, 8010 Graz, Austria.
The Journal of Physical Chemistry. A
|July 27, 2016
Summary
Time-resolved photoelectron-photoion coincidence (PEPICO) experiments reveal acetone molecule fragmentation pathways. This technique precisely tracks molecular dynamics and dissociation, crucial for understanding complex photochemical reactions.
Area of Science:
- Physical Chemistry
- Molecular Dynamics
- Spectroscopy
Background:
- Investigating photoinduced dynamics in molecules requires understanding laser-induced fragmentation.
- Time-resolved pump-probe photoionization spectroscopy is a key technique for such studies.
- Complex relaxation pathways can complicate the interpretation of molecular behavior.
Purpose of the Study:
- To investigate the excited-state dynamics of isolated acetone molecules using time-resolved pump-probe photoionization.
- To unambiguously identify and differentiate distinct pump-probe ionization channels in acetone.
- To quantitatively determine fragmentation behavior and dissociation timing.
Main Methods:
- Utilized time-resolved photoelectron-photoion coincidence (PEPICO) experiments.
- Employed two-photon (269 nm) excitation of isolated acetone molecules.
- Analyzed fragmentation patterns and time evolution for individual ionization channels.
Main Results:
- Successfully identified three distinct pump-probe ionization channels in acetone.
- PEPICO detection enabled separate observation of fragmentation behavior and time evolution for each channel.
- Quantified fragment-to-parent branching ratios and determined dissociation timing (neutral vs. ion).
Conclusions:
- Coincidence detection is vital for interpreting complex time-resolved photochemical studies.
- PEPICO provides high selectivity for observing fragmentation dynamics in molecules with multiple relaxation pathways.
- The study clarifies dissociation mechanisms in excited acetone molecules.
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