Real-time probing of Energy Dissipation Processes in Solvated Clusters

溶剂化团簇中能量耗散过程的实时探测

• 批准号: 08454177
• 负责人: OHSHIMA Yasuhiro
• 金额: $ 4.74万
• 依托单位: Kyoto University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (B)
• 财政年份: 1996
• 资助国家: 日本
• 起止时间: 1996 至 1997
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08454177/
• 关键词: Clusters; ps Time-Resolved Spectroscopy; Solvation; Energy Dissipation; Laser-Induced Fluorescence; Charge-Transfer; Inter-System Crossing; 電子移動反応; 系間交差

The present research project aims to microscopic understanding on the energy dissipation processes in solvated clusters through ultrafast time-resolved measurements. Owing to the improvement in the experimental setup, such as the vacuum chambers and laser systems, the following results have been achieved.1. The 1 : 1 cluster of 9,9'-bianthryl (BA) with water has been studied for detailed characterization of the twisted intramolecular charge transfer (TICT) reaction in BA.The torsional potential of BA in the cluster has been determined form the laser-induced-fluorescence observation of the torsional progressions. The potential in the cluster is much different from that in the monomer, indicating considerable modification in the electronic character of BA by complexation, as well as steric repulsion between BA and water. The ps time-resolved fluorescence measurements have shown that the TICT rate has no appreciable dependence on excitation energy or solvent isotopic substitution. This ob … More servation confirms that the TICT reaction proceeds via "sequential" mechanism ; the initially prepared level is predominately coupled to intermediate levels with high vibrational excitation of torsional motion, which further relax to the final levels in the charge-separated state. This result demonstrates the importance of the torsional motion in the dynamics of TICT reactions.2. The water-solvated clusters of 9-acridone (AD) have been studied to explore the microscopic solvation effect on inter-system crossing (ISC) in AD.The fluorescence quantum yield is greatly enhanced with increasing order of solvation. Especially, drastic change with>200-fold increase caused by addition of only one water to the monomer indicates the crossover of the reaction mechanism form the direct ISC to the second-order ISC.Structural characterization by JR-UV double resonance spectroscopy combined with ab initio MO calculation has shown that water is hydrogen-bonded to C=O of AD in the 1 : 1 cluster. These results validates the site-selective microsolvation effect on ISC. Less

本研究项目旨在通过超快时间分辨测量对溶剂化团簇中的能量耗散过程进行微观理解。由于改进了实验装置，如真空室和激光系统，取得了以下结果。研究了9，9‘-联菲(BA)与水的1：1团簇，对BA中扭曲的分子内电荷转移(TICT)反应进行了详细的表征。通过激光诱导荧光观察扭转过程，确定了BA在该团簇中的扭转势。团簇中的电势与单体中的电势有很大的不同，这表明BA的电子性质由于络合作用以及BA与水之间的空间斥力而发生了很大的变化。PS时间分辨荧光测量表明，TICT速率与激发能或溶剂同位素取代度没有明显的关系。这是ob…更多的观察证实，TICT反应是通过“顺序”机制进行的；最初制备的能级主要耦合到具有高振动激发的扭转运动的中间能级，这些中间能级进一步松弛到电荷分离状态的最终能级。这一结果证明了扭转运动在TICT反应动力学中的重要性。研究了9-吖啶酮(AD)水溶剂化团簇的微观溶剂化对体系间交叉(ISC)的影响。随着溶剂化程度的增加，荧光量子产率大大提高。特别是单体中只加1个水而使~gt；增加200倍的剧烈变化，表明反应机理从直接ISC向二级ISC转变。JR-UV双共振谱结合从头算分子轨道计算结果表明，水与AD的C=O在1：1的簇中形成氢键。这些结果验证了位置选择性微溶剂化对ISC的影响。较少

项目成果

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H.Kohguchi 等人：“HCCS 自由基的 A^1π^1-X^2π 跃迁中的激光诱导荧光光谱和量子拍观测”《化学物理快报》254. 397-402 (1996)。

Y.Ohshima,et al.: "Rotational spectroscopy of jet-cooled molecular ions and ion complexes" Chenical Physics Letters. 256. 635-640 (1996)

Y.Ohshima 等人：“喷射冷却分子离子和离子复合物的旋转光谱”《化学物理快报》。

Y.Ohshima,et al.: "Rotational spectroscopy of jet-cooled molecular ions and ion complexes" Chemical Physics Letters. 256. 635-640 (1996)

Y.Ohshima 等人：“喷射冷却分子离子和离子复合物的旋转光谱”《化学物理快报》。

M.Matumura,et al.: "Fourier-transform microwave spectroscopy of the argon-diacetylene van der Waals complex" Journal of Molecular Spectroscopy. 185. 178-184 (1997)

M.Matumura 等人：“氩-二乙炔范德华复合物的傅里叶变换微波光谱”《分子光谱学杂志》。

M.Matumura, et al.: "Fourier-transform microwave spectroscopy of the argon-diacetylene van der Waals complex" Journal of Molecular Spectroscopy. 185. 178-184 (1997)

M.Matumura 等人：“氩-二乙炔范德华复合物的傅立叶变换微波光谱”《分子光谱学杂志》。