Theoretical study on static (hyper)polarizabilities for polyimide by the elongation finite-field method |
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| Authors: | Guang-Tao Yu Wei Chen Yuuichi Orimoto Yuriko Aoki |
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| Affiliation: | 1. Faculty of Engineering Sciences, Department of Material Sciences , Kyushu University , 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan;2. Faculty of Engineering Sciences, Department of Material Sciences , Kyushu University , 6-1 Kasuga-Park, Fukuoka, 816-8580, Japan;3. Group, CREST , Japan Science and Technology Agency (JST) , Kawaguchi Center Building, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan |
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| Abstract: | The elongation finite-field method is applied to calculate (hyper)polarizabilities of polyimides PMDA/DMDB, PMDA/ODA, and PMDA/TFDB. The nonlinear optical (NLO) properties of planar structures of three polyimides are compared to those of their twist structures. It is found that all α and γ values of the planar structures are larger than the corresponding values of the twist structures, which may be attributed to the fact that π-conjugation of twist structures is decreased compared with the planar structures. All β values of planar and twist structures oscillate regularly along with elongating the chain. Moreover, effect of two side-groups –CH3 and –CF3 on the NLO properties of PMDA/DMDB and PMDA/TFDB is investigated. |
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| Keywords: | elongation method nonlinear optics polyimide |
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