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Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
High energy proton ejection from hydrocarbon molecules driven by highly efficient field ionization.
Stefan Roither1, Xinhua Xie, Daniil Kartashov
1Photonics Institute, Vienna University of Technology, Vienna, Austria, EU.
Physical Review Letters
|May 24, 2011
Summary
Energetic protons are ejected during the Coulomb explosion of hydrocarbon molecules. This occurs via enhanced ionization across multiple carbon-hydrogen bonds, even at moderate laser intensities.
Area of Science:
- Physical Chemistry
- Molecular Physics
- Laser-Matter Interactions
Background:
- Polyatomic hydrocarbon molecules are fundamental in chemistry.
- Understanding molecular fragmentation under intense laser fields is crucial for controlling chemical reactions.
- Previous studies have explored laser-induced dissociation, but concerted explosions from high charge states require further investigation.
Purpose of the Study:
- To investigate the mechanisms of energetic proton ejection from hydrocarbon molecules under intense ultrashort laser pulses.
- To analyze the fragmentation channels contributing to proton emission.
- To understand the role of enhanced ionization in molecular Coulomb explosions.
Main Methods:
- Exposure of hydrocarbon molecules to 790 nm, 27 fs laser pulses.
- Utilizing multiparticle coincidence imaging to resolve fragmentation pathways.
- Analyzing proton energy spectra to determine contributions from individual channels.
Main Results:
- Complete molecular fragmentation observed at peak intensities of ~10^14 W/cm^2.
- Protons are ejected via concerted Coulomb explosion from unexpectedly high charge states.
- Experimental observations align with models of enhanced ionization occurring simultaneously at multiple C-H bonds.
Conclusions:
- Hydrocarbon molecules undergo rapid, complete fragmentation when exposed to intense ultrashort laser pulses.
- Concerted Coulomb explosion from high charge states is a significant pathway for proton ejection.
- Enhanced ionization across multiple C-H bonds plays a key role in this fragmentation process.
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