Analysis of rotational diffusion of coumarin laser dyes

Rotational diffusion analysis of two laser dyes, coumarin 6 and coumarin 30, has been studied in alkane and alcohol solvents using steady-state and time-resolved fluorescence depolarization methods. The rotational diffusion times of these probes vary linearly as a function of viscosity over the range of temperature studied. It is observed that the rotational diffusion time measurements of molecules in alcohol and alkane have relaxation times typically on the order of picoseconds, though they are greater in alcohol than in alkane solvents. However, it was observed that coumarins rotate faster in n-hexane and n-heptane than in n-propanol and n-butanol solvents, and the observed results are discussed in the last section.

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Temperature-dependent reorientation dynamics of laser dyes in alkane and alcohol solvents

Canadian Journal of Physics ◽

10.1139/cjp-2012-0540 ◽

2013 ◽

Vol 91 (9) ◽

pp. 677-681 ◽

Cited By ~ 7

Author(s):

Y.F. Nadaf ◽

C.G. Renuka ◽

U.S. Raikar

Keyword(s):

Relaxation Times ◽

Laser Dyes ◽

Temperature Dependent ◽

Fluorescence Depolarization ◽

Time Resolved ◽

Structural Differences ◽

Reorientation Time ◽

Reorientation Dynamics ◽

Alcohol Solvents ◽

Coumarin 6

The rotational dynamics of similar sized coumarin 6 (C6), coumarin 7 (C7), and coumarin 30 (C30) laser dyes has been studied in alkane and alcohol solvents using steady-state and time-resolved fluorescence depolarization methods. The estimated rotational reorientation times of these probes are observed to vary linearly as a function of viscosity over the range of temperatures studied. It is found that the rotational reorientation time measurements of these molecules in alcohol and alkane typically have relaxation times on the order of picoseconds. The rotational reorientation times of the C7 molecule are greater than those of the C6 and C30 molecules. It was observed that C7 rotates faster in both the solvents than C6 and C30, indicating that the effects of the medium and structural differences of molecules lead to slower rotation.

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Molecular Movements and Dynamics in Solutions Studied by Fluorescence Depolarization Measurement

Collection of Czechoslovak Chemical Communications ◽

10.1135/cccc19930213 ◽

1993 ◽

Vol 58 (2) ◽

pp. 213-233 ◽

Cited By ~ 5

Author(s):

Zuzana Limpouchová ◽

Karel Procházka ◽

Vlastimil Fidler ◽

Jiří Dvořák ◽

Bohumil Bednář

Keyword(s):

Energy Transfer ◽

Rotational Diffusion ◽

Experimental Studies ◽

Theoretical Models ◽

Reorientational Motion ◽

Fluorescence Depolarization ◽

Time Resolved ◽

Langevin Model ◽

Theoretical Predictions ◽

Media Systems

Theories allowing interpretation of the results of time-resolved polarization spectrofluorimetry in solutions are reviewed and their applicability under various conditions is discussed. For the reorientation of rigid molecules in an isotropic medium, the most frequently employed models are presented, such as rotational diffusion model, the Fokker-Planck-Langevin model, etc. Systems with internal rotation, systems in anisotropic media, systems with a complex electron relaxation and systems with energy transfer are discussed as examples of more complex systems. A special attention is devoted to the polarization fluorimetry of probes bound to/or sorbed at polymer and biopolymer chains. The review focuses on theoretical models of reorientational motion for interpretation of fluorescence anisotropy decays. Experimental studies and computer simulations are discussed only when it is necessary for comparison with theoretical predictions. Complicated models for simultaneous reorientational motion and energy transfer, solvent relaxation, etc., although very important for many applications, exceed the scope of this review and are mentioned only very briefly.

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