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Ultrafast photochemistry in liquids
Arnulf Rosspeintner1, Bernhard Lang, Eric Vauthey
1Department of Physical Chemistry, University of Geneva, CH-1211 Geneve 8, Switzerland.
Annual Review of Physical Chemistry
|January 10, 2013
Summary
Ultrafast photochemical reactions occur during excited-state relaxation, deviating from equilibrium predictions. These dynamics, influenced by vibrational and solvent modes, challenge traditional photochemical rules like Kasha's and Vavilov's.
Area of Science:
- Photochemistry
- Chemical Physics
- Molecular Dynamics
Background:
- Ultrafast photochemical processes can occur concurrently with excited-state relaxation.
- Relaxation involves vibrational and solvent modes on femtosecond to picosecond timescales.
- This can lead to reaction dynamics differing from those of equilibrated excited states.
Purpose of the Study:
- To review vibrational and solvent relaxation processes in photochemistry.
- To overview key ultrafast photochemical reaction classes: electron transfer, proton transfer, and isomerization.
- To illustrate how nonequilibrium effects influence these reaction dynamics.
Main Methods:
- Theoretical review of vibrational and solvent relaxation.
- Overview of ultrafast photochemical reaction mechanisms.
- Case studies illustrating nonequilibrium effects.
Main Results:
- Excited-state population decay can be nonexponential and wavelength-dependent.
- These dynamics may contradict the Kasha and Vavilov rules.
- Nonequilibrium effects significantly alter reaction pathways.
Conclusions:
- Understanding nonequilibrium dynamics is crucial for ultrafast photochemistry.
- These processes offer insights beyond traditional photochemical models.
- Further research into vibrational and solvent effects is warranted.
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