ISSN:
1089-7690
Source:
AIP Digital Archive
Topics:
Physics
,
Chemistry and Pharmacology
Notes:
Monte Carlo simulations are applied to imitate the incoherent electronic energy transfer among identical luminescent molecules in three-dimensional isotropic systems. The interacting molecules are then either rapidly or slowly rotating compared to the time scale of emission and we refer to these as the fast and slow cases, respectively. The time dependence of the excitation probability of the initially excited molecule [Gs(t)] and the mean square displacement [〈R2(t)〉] of the initial excitation are simulated for the slow and fast cases. The results are compared to those obtained from the analytical model of Gochanour, Andersen, and Fayer (the GAF theory) and to some extent to the computer method of Riehl. In the fast case and at a reduced concentration being less than two both Gs(t) and 〈R2(t)〉 are in very good agreement with the so-called three-body GAF theory. The deviations found at higher concentrations are likely due to the omission of higher orders of coupling in the GAF theory. For the slow case the GAF theory is developed exactly only to two-body order, and the agreement between theory and simulations is not so encouraging. However, if an approximative three-body term is included for Gs(t) the agreement becomes excellent for a large range of concentrations. Finally, the emission anisotropy [r(t)] of a donor–donor system is simulated for the slow case. The emission from any donor in the system, i.e., not necessarily the one excited initially, is thereby considered. The simulated r(t) agrees very well with the approximation of r(t)=(2/5)⋅Gs(t) which justifies the so-called Galanin model.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.455506
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