1986 Fiscal Year Final Research Report Summary
Electron Spin Echo (ESE) Studies on Electronic State of Polyacetylene
| Project/Area Number |
60470098
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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 |
高分子物性
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| Research Institution | Hokkaido University |
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Principal Investigator |
JUNKICHI Sohma Faculty of Engineering, Hokkaido University Prof., 工学部, 教授 (00001115)
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| Co-Investigator(Kenkyū-buntansha) |
SHIMOYAMA Yuhei Hokkaido University of Education, Hakodate Associate Prof., 函館分校, 助教授 (50123948)
SHIOTANI Masaru Faculty of Engineering, Hokkaido University Instructor, 工学部, 助手 (80002137)
TABATA Masayoshi Faculty of Engineering, Hokkaido University Associate Prof., 工学部, 助教授 (50091476)
OHNO Keiichi Faculty of Engineering, Hokkaido University Associate Prof., 工学部, 助教授 (00001298)
YOSHIDA Hiroshi Faculty of Engineering, Hokkaido University Prof., 工学部, 教授 (20027410)
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| Project Period (FY) |
1985 – 1986
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| Keywords | Polyacetylene / Electron Spin Echo (ESE) / Spin-lattice relaxation / スピン-スピン緩和 |
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| Research Abstract |
At first a method for characterization of polyacetylene, for which chemical analysis is not so easy because of its insolubility, was established mainly by using the CP-MAS <^(13)C-NMR> . It was found by this characterization method that polyacetylene is easily degraded by exposing to air even for short time at room temperature. Thus, it is necessary to characterize a polyacetylene sample before any measurements in order to find out whether or not the sample is pristine.
Both spin-lattice relaxation time and spin-spin relaxation time were determined for polyacetylene by the electron spin echo (ESE) method. Same quantities were also evaluated for the same sample from either the saturation behavior or the line-shape, which were observed by the stationary (CW) method. It was found that the values evaluated by the two different methods, ESE and CW, did not coincide each other. This descrepancy means that assumptions needed for evaluation of the relaxation times from the CW data do not hold for polyacetylene, while ESE is more direct method to observed these relaxation times. This result indicates that most of the relaxation times, which were published in the literatures, are less reliable, because these values were determined by the CW method.
The temperature variations of the relaxation times determined by the ESE indicates that the unpaired electron in polyacetylene is immobile and localized just like a free radical. This conclusion means that the unpaired electron are different from the conduction electrons being highly mobile. And this conclusion is compatible with Su's model in which the unparied electrons localized within ca. 14 carbons.
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Research Products
(8 results)
