Time-dependent fluorescence in nanoconfined solvents: linear-response approximations and Gaussian statistics.

Abstract

The time-dependent fluorescence of a model dye molecule in a nanoconfined solvent is used to test approximations based on the dynamic and static linear-response theories and the assumption of Gaussian statistics. Specifically, the results of nonequilibrium molecular-dynamics simulations are compared to approximate expressions involving time correlation functions obtained from equilibrium simulations. Solvation dynamics of a model diatomic dye molecule dissolved in acetonitrile confined in a spherical hydrophobic cavity of radius 12, 15, and 20 Å is used as the test case. Both the time-dependent fluorescence energy, expressed as the normalized dynamic Stokes shift, and the time-dependent position of the dye molecule after excitation are examined. While the dynamic linear-response approximation fails to describe key aspects of the solvation dynamics, assuming Gaussian statistics reproduces the full nonequilibrium simulations well. The implications of these results are discussed.

DOI: 10.1063/1.3626825

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Cite this paper

@article{Laird2011TimedependentFI, title={Time-dependent fluorescence in nanoconfined solvents: linear-response approximations and Gaussian statistics.}, author={Brian B. Laird and Ward H Thompson}, journal={The Journal of chemical physics}, year={2011}, volume={135 8}, pages={084511} }