アルファ,オメガ,ディフェニルポリエネスにおける光刺激状態の対称性スイッチング
Yasutomo Nagano1, Tadaaki Ikoma, Kimio Akiyama
1Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Sendai 980-8577, Japan.
Journal of the American Chemical Society
|November 13, 2003
まとめ
この研究では,スペクトロスコピーとDFT計算を使用して,ディフェニルポリアイン (DPY) の興奮状態を調査しています. より長いDPY分子は,ポリエネと異なるユニークなA(u) 対称性状態と減少した光学反応を示します.
科学分野:
- 物理化学 物理化学
- コンピューティング・ケミストリー
- スペクトロスコーピーは,スペクトロスコーピーを用います.
背景:
- アルファ・オメガ・ディフェニルポリリン (DPY) は,非線形光学における潜在的な応用を持つ結合系である.
- 興奮状態の特性を理解することは,光学的行動の調節に極めて重要です.
研究 の 目的:
- 異なる数のトリプルボンド (N=1-6) を有するディフェニルポリリン (DPY) の低濃度興奮単体状態を包括的に研究する.
- 分子構造,興奮状態の対称性,光学的性質の関係を解明する.
- 長がスペクトル特性と非線形光学応答に及ぼす影響を調査する.
主な方法:
- 密度関数理論 (DFT) による分子軌道 (MO) 計算.
- 吸収および光スペクトロスコピー.
- バイブロニック構造,寿命,およびソルバトクロミックシフトの分析.
主要な成果:
- 光スペクトルの異なる振動モードを観察し,結合長と相関しています.
- 短いDPYと長いDPYにおける支配的な低下の興奮状態として1(1)B(1u) と1(1)A(u) を特定した.
- 長いDPYで許可された (1(1) B(1u) <-- S(0)) と禁止された (1(1) A(u) <-- S(0)) 移行が検出されました.
- DPYのNの増加とともに振動器の強さの低下が観察され,これはディフェニルポリエネと対照的です.
- 1(1) B(1u) と 2(1) B(1u) 状態の構成相互作用は,振動器の強さのN依存性を説明する.
結論:
- A(u) 対称性を持つ低い興奮状態は,ポリエネに存在しないポリエネの特徴的な特徴です.
- 観測されたスペクトル変化と,より長いDPYにおける振動器の強度の低下は,特定の電子相互作用に起因する.
- 発見は,ポリアニンの光学反応を制御する構造-特性関係についての洞察を提供します.
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