- 著者
-
辻 勇人
金澤 悠紀
江原 正博
ツジ ハヤト
エハラ マサヒロ
- 出版者
- 神奈川大学総合理学研究所
- 雑誌
- Science journal of Kanagawa University = 神奈川大学理学誌 (ISSN:18800483)
- 巻号頁・発行日
- vol.31, pp.61-64, 2020
Geometric optimization of the excited states of n-Si5Me12 and n-Si7Me16 was performed using time-dependent density functional theory calculations to compare their structures and emission properties. It was found that the geometry of n-Si5Me12 changes from alltransoid in the ground state to all-anti in the excited state, whereas that of n-Si7Me16 remains all-transoid in both states. This is related to elongation of the Si-Si bond lengths in the excited state, showing σσ* : those of pentasilane elongate to 2.45-2.49 Å with bond angles up to 141° in the excited state, which facilitates its conformation to relax all-anti by releasing the 1,3-repulsion between the methyl groups. Meanwhile, those of heptasilane (less than 2.434 Å and 125°) do not elongate as much as those of pentasilane, which restrict its conformation similar to that in the ground state. Calculated emission wavelengths and oscillator strengths of these oligosilanes effectively reproduced the experimental data: large and small Stokes shifts in pentasilane and heptasilane, respectively, were estimated in agreement with calculated geometric changes.原著2019年度神奈川大学総合理学研究所共同研究助成論文