Reliability of parameters obtained from time resolved fluorescence polarization in macroscopically isotropic liquid crystals and membrane vesicles
Arcioni A.; Tarroni R.; Zannoni C., 1991: Reliability of parameters obtained from time resolved fluorescence polarization in macroscopically isotropic liquid crystals and membrane vesicles. Journal of the Chemical Society Faraday Transactions 87(15): 2457-2466
The practical possibility of extracting static and dynamic parameters from fluorescence anisotropy decays of rod-like probes in membrane vesicles and other macroscopically isotropic samples with a locally ordered structure, such as cubic liquid crystal or unoriented polymer liquid crystal is discussed. Particular attention is paid to the obtainment of the fourth-rank order parameter (P4). For monodomain samples, global target analysis of samples at different temperatures has proved helpful. To test if this is true here as well, simulated single-photon-counting intnsnities at various temperatures have been prepared using a mean-field model and then analysed both individually and globally by means of target analysis. The results show that there is little hope of obtaining (P4) from macroscopically unoriented systems, except for some limiting cases. On the other hand, the recovery of (P2) and of the tumbling diffusion coefficient, D.perp., seems to be quite insensitive to the selected model for the anisotropic potential.Other references
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