2023-01-27T12:29:53Z
https://soar-ir.repo.nii.ac.jp/oai
oai:soar-ir.repo.nii.ac.jp:00014505
2022-12-14T04:05:05Z
1309:1314:1458:1461
15-4-6 : 光学的および電気的諸機能を持つ巨大分子の分子設計
光･電気応答性巨大分子の研究
野村, 泰志
The discovery of carbon tubules or nanotubes has greatly stimulated researrh work on single-wall nanotubes (SWNT’s), which are characterized by a chiral vector (n,m)≡na+mb (a and b: the unit vectors of the hexagonal honeycomb lattice) with integers n and m. The optical property one of the intersting subjects on SWN’s. In this work, we consider polarization-dependent optical properties of the open (N,N) SWNT’s C4N+2NnH4N(N=5-8; N=0-11) with the DNd or DNh symmetry, Hereafter transitions induced by lights polarized along the cylindrical and transversal axes are called z- and (x,y)-transitions, respectively. To obtain the excitation energies and the oscillator strengths, we employ the Tamm-Dancoff approximation (TDA) scheme in the CNDO/S approximation. We analyze the optical transitions of the SWNT’s for the longest absorption edges and the prominent peaks in the low energy region, and also discuss their dependence on the tube radius (N) and length (n). We first note that the HOMO-LUMO gap energies periodically decrease with n, taking minimum values at n=1,4, 7, 10. Such a periodic decrease has been shown for the calved (5,5) nanotubes. According to the CNDO/S-TDA data, the low-lying optical transitions are practically the π-π transitions including the HOMO’s and LUMO’s (and their neighboring MO 'S). It is shown that excitation energies of the lowest z- and (x,y)-transitions almost periodically decrease with n but not with N. Oscillator strengths for the second lowest z-transitions (pron7inentpeaks) increase with both N and n. On the other hand, for the lowest (x,y)-transitions (prominent peaks), they lnrcease With N but not with n. The expansion of the SWNT system in the transversal directions increases the oscillator strength for both the low-lying z- and (x,y)-transitions, though the expansion along the cylindrical axis increases it for the z-transitions but not for the (x,y)-transitions,
Article
先進ファイバー工学研究教育拠点研究成果報告書 11: 101-102(2005)
信州大学繊維学部
2005-03-31
jpn
research report
VoR
http://hdl.handle.net/10091/13476
https://soar-ir.repo.nii.ac.jp/records/14505
AA1200368X
先進ファイバー工学研究教育拠点研究成果報告書
11
101
102
https://soar-ir.repo.nii.ac.jp/record/14505/files/AFSTT11-406.pdf
application/pdf
771.0 kB
2015-09-28