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08:22
Measurement of Ultrafast Vibrational Coherences in Polyatomic Radical Cations with Strong-Field Adiabatic Ionization
Published on: August 6, 2018
Real-time evolution of the valence electronic structure in a dissociating molecule
Ph Wernet1, M Odelius, K Godehusen
1Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse 15, D-12489 Berlin, Germany. wernet@helmholtz-berlin.de
Physical Review Letters
|August 8, 2009
Summary
Researchers observed the electronic structure of bromine molecules (Br2) as they dissociate. This study reveals a rapid transition period where molecules become intermediate between atoms and molecules, with bond breaking occurring in a surprisingly short time.
Area of Science:
- Chemical Physics
- Molecular Dynamics
- Spectroscopy
Background:
- Understanding molecular dissociation dynamics is crucial for chemical reactions.
- Valence electronic structure governs molecular bonding and reactivity.
Purpose of the Study:
- To investigate the real-time electronic structure changes during gas-phase Br2 molecule dissociation.
- To determine the timescale of bond breaking in photoexcited Br2.
Main Methods:
- Utilizing time-resolved valence band photoelectron spectroscopy.
- Achieving a temporal resolution of 135 femtoseconds (fs).
- Mapping the occupied valence electronic structure of photoexcited Br2.
Main Results:
- Observed shifting and mixing of valence energy levels during dissociation.
- Identified a transition period where Br2 is intermediate between molecular and atomic states.
- Determined a surprisingly short bond-breaking time by monitoring the emergence of atomic photoelectron multiplet structure.
Conclusions:
- The dissociation of Br2 is a rapid process.
- The electronic structure undergoes significant changes, reflecting a transition from molecular to atomic character.
- Time-resolved photoelectron spectroscopy provides insights into ultrafast chemical dynamics.
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