1990 Fiscal Year Final Research Report Summary
Fractals and Excitation Transfer in Molecular Assemblies
| Project/Area Number |
01470002
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
物理化学一般
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| Research Institution | Hokkaido University |
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Principal Investigator |
YAMAZAKI Iwao Hokkaido Univ., Fac. of Eng. Pro.,, 工学部, 教授 (80002111)
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| Co-Investigator(Kenkyū-buntansha) |
NISHIMURA Yoshinobu Hokkaido Univ., Fac. of Eng. Inst.,, 工学部, 助手 (60218211)
TAMAI Naoto Hokkaido Univ., Fac. of Eng. Inst.,, 工学部, 助手 (60163664)
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| Project Period (FY) |
1989 – 1990
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| Keywords | Fractal / Energy Transfer / Langmuir-Blodgett Films / Vesicle / Picosecond Laser |
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| Research Abstract |
Electronic excitation transfer has been studied with several kinds of molecular assemblies such as vesicles and Langmuir-Blodgett films with a view to establishment of the fractal structure in distribution of guest molecules. Dynamics of excitation transfer was investigated by means of a picosecond time-resolved fluorescence spectrophoto-meter. It was found that the fractal behaviors are essential among molecular assemblies in spatialdistribution of chromophores or in siteーenergy distribution, and that the morphology of molecular assembly frameworks affects the dynamics of energy relaxation processes. The fluorescence decays can be analyzed by an equation including a stretched exponential function. The mechanisms of singlet excitation energy relaxation were interpreted in terms of
(1) the energy trapping at acceptor sites under the fractal distribution with the fractal dimension of 1.3 -1.5, and
(2) the energy migration among energetically disordered monomer sites represented by ultrametric space (hierarchical energy distribution).
The diffusion length of the excitation energy transport was estimated from the dynamic stokes shift and the fluorescence decay curve.
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