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Ultrafast dynamics of isolated fluorenone.
Juliane Köhler1, Patrick Hemberger, Ingo Fischer
1Institut für Physikalische und Theoretische Chemie, Universität Würzburg, Würzburg.
The Journal of Physical Chemistry. A
|November 4, 2011
Summary
Ultrafast dynamics of 9-fluorenone were investigated using advanced spectroscopy. Energy redistribution occurs within 50 femtoseconds, followed by internal conversion to the S(1) state within 0.4 picoseconds.
Area of Science:
- Physical Chemistry
- Molecular Dynamics
- Spectroscopy
Background:
- Understanding the excited-state decay pathways of organic molecules is crucial for photochemistry and photophysics.
- 9-fluorenone is a key chromophore whose ultrafast dynamics are not fully elucidated.
Purpose of the Study:
- To investigate the ultrafast dynamics of isolated 9-fluorenone following excitation.
- To determine the time scales of energy redistribution and internal conversion processes.
Main Methods:
- Femtosecond time-resolved photoionization spectroscopy
- Femtosecond time-resolved photoelectron spectroscopy
- Time-Dependent Density-Functional Theory (TD-DFT) calculations
Main Results:
- Excitation to the S(6) state leads to rapid energy redistribution within 50 femtoseconds.
- Internal conversion to the long-lived S(1) state occurs within 0.4 picoseconds.
- The S(1) state has a lower bound lifetime of 20 picoseconds.
Conclusions:
- The study reveals a multistep deactivation pathway for 9-fluorenone.
- Experimental findings are supported by TD-DFT calculations of excited state properties.
- Provides critical insights into the photophysical behavior of 9-fluorenone.
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