[ Previous / Next Abstract | Issue Table of Contents | Bottom of Page ]

The Journal of Chemical Physics -- March 15, 1987 -- Volume 86, Issue 6, pp. 3273-3282

Criteria for the rapid diffusion limit of fluorescence energy transfer

Kazuhiko Kinosita, Jr., Tsutomu Kouyama, and Akira Ikegami

The Institute of Physical and Chemical Research, Hirosawa 2-1, Wako-shi, Saitama 351-01, Japan

(Received 9 June 1986; accepted 12 December 1986)

Excitation energy transfer in a system where the spatial relationship between the donor and acceptor is not fixed generally leads to a nonexponential decay of donor fluorescence. A single-exponential decay, however, is expected as a limiting form when the diffusion of the donors and/or acceptors is sufficiently rapid. The exponential character at the rapid diffusion limit will greatly facilitate the analysis of experimental data. In this paper a theoretical framework is presented that allows the calculation of the criterion for the rapid diffusion limit. Explicit criteria are given for various donor–acceptor geometries, all for the case of energy transfer via the resonance interaction of the Förster type. The criteria, except for the cases of densely distributed acceptors under a wide surface, have a common form D_Da⁴/R₀, where _D is the lifetime of donor fluorescence in the absence of acceptors, D is the sum of diffusion coefficients of the donor and acceptor, a is the distance of closest approach between the donor and acceptor, R₀ is the critical distance for energy transfer, and is a geometrical constant with a value less than one. Exponential decays are not easily obtained when acceptors are densely distributed under a wide surface. The results are compared with the criterion given earlier by Thomas et al. [D. D. Thomas, W. F. Carlsen, and L. Stryer, Proc. Natl. Acad. Sci. U.S.A. 75, 5746 (1978)]. Experimental aspects, such as the effect of heterogeneity in a sample, are also discussed. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

doi:10.1063/1.451986
PACS: 87.15.Mi        Additional Information

  The American Institute of Physics is a member of CrossRef.

[JCP Home] [All Online Issues: Browse | Search] [SPIN Database: Browse | Search] [HELP] [EXIT]