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Time-Resolved Fluorescence Anisotropy from Single Molecules for Characterizing Local Flexibility in Biomolecules

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Stochastic model for photoinduced anisotropy.

Valentina Cantatore¹, Giovanni Granucci, Maurizio Persico

¹Dipartimento diChimica e Chimica Industriale, Università di Pisa, v.Risorgimento 35, I-56126 Pisa, Italy.

Journal of Computational Chemistry

|February 15, 2012

Summary

We developed a new model to simulate how light changes molecular orientation and causes anisotropy. This method connects single-molecule behavior to large-scale effects, crucial for understanding photoisomerization in materials.

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Area of Science:

Photochemistry
Materials Science
Computational Chemistry

Background:

Photoinduced anisotropy is key in materials science.
Understanding molecular behavior under light is complex.
Existing models often lack molecular-scale detail.

Purpose of the Study:

To present a novel stochastic model for photoinduced anisotropy kinetics.
To link single chromophore dynamics to bulk material properties.
To investigate the interplay of photoisomerization and anisotropy.

Main Methods:

Developed a stochastic model for chromophore kinetics.
Incorporated single chromophore photoorientation, photoisomerization, and rotational diffusion data.
Utilized molecular dynamics simulations for input parameters.
Connected molecular-scale processes to long-timescale anisotropy development.

Main Results:

The model successfully simulates photoinduced anisotropy in molecular chromophores.
Demonstrated the connection between single-molecule dynamics and bulk anisotropy.
Azobenzene test case highlights the interplay between photoisomerization and anisotropy.

Conclusions:

The stochastic model provides a computational link between molecular behavior and macroscopic anisotropy.
This approach offers new insights into light-induced material property changes.
The method is applicable to various photoresponsive molecular systems.