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Diffusional fluorescence quenching of aromatic hydrocarbons
Clelia Canuel1, Sophie Badre, Henning Groenzin
1Schlumberger-Doll Research, Ridgefield, Connecticut 06877, USA.
Applied Spectroscopy
|December 9, 2003
Summary
Fluorescence quenching rates of aromatic hydrocarbons by oxygen and halogenated organics were measured. Oxygen quenching is diffusion-controlled, while halogenated organic quenching correlates with electronic state energy differences.
Area of Science:
- Photochemistry
- Physical Chemistry
- Spectroscopy
Background:
- Fluorescence quenching is a critical process in photochemistry.
- Understanding quenching mechanisms provides insights into molecular interactions.
Purpose of the Study:
- To quantify fluorescence quenching rates of aromatic hydrocarbons.
- To investigate quenching mechanisms by molecular oxygen and halogenated organics.
- To explore structure-activity relationships in quenching processes.
Main Methods:
- Experimental measurement of fluorescence intensity and lifetime.
- Application of linear Stern-Volmer analysis.
- Systematic variation of fluorophore and quencher molecules.
Main Results:
- Molecular oxygen quenching rates are diffusion-controlled and independent of fluorophore excitation energy.
- Halogenated organic quenching rates vary significantly (factor of 965).
- Quenching rates correlate with the energy difference between quencher and fluorophore excited states.
Conclusions:
- Stern-Volmer analysis is valid for these quenching systems.
- Quantum two-level mixing model explains halogenated organic quenching.
- Coupling interaction energy is approximately 2500 cm(-1).