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Basic measurements of partial orders in solution

解中偏序的基本测量

基本信息

批准号：
12440158
负责人：
IWATA Koichi
金额：
$ 9.6万
依托单位：
The University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

Kinetics of bimolecular chemical reactions between trans-stilbene or biphenyl and carbon tetrachloride have been measured with femtosecond time-resolved spectroscopic methods. The observed kinetics are well explained by theories of diffusion-controlled reactions. This result suggests that the translational motion of molecules in solution is described well as diffusion motion after a few picosecond time interval.Mechanism of a double proton transfer reaction induced by photoexcitation of the 2-aminopyridin / acetic acid complex has been examined. Experimental results from picosecond time-resolved spectroscopy show that this double proton transfer proceeds with a stepwise mechanism. It is crucial to keep the molecular complex between 2-aminopyridine and acetic acid for at least a few picoseconds for this reaction.Temperature dependence of the trans-cis isomerization rate as well as the shape of the Raman bands of the first excited singlet (S_1) state of trans-stilbene have been measured in three different solvents, hexane, octane, and decane. The relation between the isomerization reaction rate and the solute-solvent interaction is discussed based on the experimental results. The dynamic polarization model, which postulates that the amplitude, duration, and frequency of the solute-solvent interaction determine both the reaction rate and the Raman band shape, explains the experimental results successfully.Trans-stilbene solubilized in the hydrophobic core of the SDS micelle is ionized by photoexcitation. From the picosecond time-resolved CARS experiments, it has been suggested strongly that the generated cation radial reaches the outer hydrophilic interface between the micelle and the bulk water within 20 ps. It has been also suggested, however, that it takes 1 to 2 ps for the electron generated simultaneously with the cation radial to reach the bulk water.

用飞秒时间分辨光谱方法研究了反式二苯乙烯或联苯与四氯化碳的双分子化学反应动力学。所观察到的动力学很好地解释了扩散控制反应的理论。这一结果表明，溶液中分子的平移运动在几皮秒的时间间隔后即被描述为扩散运动，并对2-氨基吡啶/乙酸络合物光激发诱导的双质子转移反应机理进行了探讨。皮秒时间分辨光谱的实验结果表明，这种双质子转移是以阶梯式的机制进行的。在正己烷、正辛烷和正癸烷三种不同的溶剂中，测定了反式二苯乙烯的反-顺异构化速率和第一激发单重态（S_1）的拉曼谱带的形状随温度的变化。根据实验结果讨论了异构化反应速率与溶质-溶剂相互作用的关系。动态极化模型假设溶质-溶剂相互作用的振幅、持续时间和频率决定了反应速率和拉曼谱带的形状，成功地解释了实验结果。从皮秒时间分辨汽车实验，它已被强烈建议，所产生的阳离子径向到达胶束和散装水之间的外部亲水界面在20 ps内。然而，也有人提出，与阳离子辐射同时产生的电子到达本体水需要1至2 ps。