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Dynamics of excitions created by a single picosecond pulse
Ciba Foundation Symposium
|February 7, 1978
Summary
This study analyzes bimolecular annihilation in finite domains, finding that fluorescence decay depends on excitation intensity and domain size. This impacts understanding exciton dynamics in photosynthesis.
Area of Science:
- Theoretical physics
- Photochemistry
- Photosynthesis research
Background:
- Bimolecular annihilation is crucial in exciton dynamics.
- Understanding these processes in finite domains is key for photosynthesis research.
- Previous models often simplified domain characteristics.
Purpose of the Study:
- To theoretically analyze bimolecular annihilation in finite domains.
- To derive expressions for quantum fluorescence yield and time dependence.
- To investigate the influence of domain parameters on fluorescence decay.
Main Methods:
- Formulation of a Pauli master equation for varying excitation sources.
- Derivation of quantum fluorescence yield and time dependence.
- Analysis of fluorescence decay under different excitation intensities and domain dimensions.
Main Results:
- Fluorescence yield depends on bimolecular exciton annihilation rate and domain dimension.
- Exciton diffusion constants are large, and photosystem II domains may contain multiple units.
- Fluorescence decay transitions from exponential to non-exponential with increased excitation hits.
Conclusions:
- Fluorescence decay shape is sensitive to excitation intensity and domain size.
- Changes in effective domain size alter fluorescence decay.
- The theory has implications for biological processes and experimental design in photosynthesis.