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Study on Microscopic Solvation Effects on Nonradiative Processes

非辐射过程微观溶剂化效应研究

基本信息

批准号：
10440172
负责人：
OHSHIMA Yasuhiro
金额：
$ 8.58万
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：
1998
资助国家：
日本
起止时间：
1998 至 2000
项目状态：
已结题

项目摘要

The present research project aims to clarifying how and why nonradiative processes in aromatic molecules are influenced by solvents surrounding them through experimental investigations on solvated clusters containing aromatic chromophores. By applying various spectroscopic methods, i.e., multiple laser resonances, massselective photoionization, and ultrafast laser spectroscopy, the following results have been achieved.1.Hydrated clusters of acridine and 9-acridone have been studied to explore molecular-level correlation between structural motifs in hydrogen-bonding networks and nonradiative processes in the chromophores. Geometries of the hydrates have been determined by comparison of experimental data(band shifts in electronic transitions and fluorescence-detected infrared spectra)with density-functional-theory calculations. Pico-second time-resolved measurements have shown that fluorescence lifetimes depend substantially on cluster sizes as well as hydrogenbonding sites. The microsco … More pic solvation effects have been explained in terms of energetics relating to closely lying(n, π^*)and(π, π^*)states, which are characteristically shifted by hydrogen bonds.2.Electronic transitions of benzene clusters in the monomer S_1-S_0 region have been reinvestigated. It has been found that previous size-assignments accepted for two decades need to be corrected, based on detailed examination of mass-selective holeburing spectra recorded for various isotopic species of dimer and trimer ion channels. New assignments have been proposed for the benzene trimer and tetramer, which resolve contradictions between experimental and theoretical results reported so far. The present data also provide information on geometry and excitation exchange interactions of the clusters.3.Geometrical structure of solvated clusters containing 9-cyanoanthracene has been determined by rotational coherence spectroscopy implemented with pico-second time-resolved pump-probe depletion. In particular, structral motif for aprotic solvent molecules, e.g., carbon dioxide, acetonitrile, and fluoroform, has been established for the first time, which will be a solid foundation for discussing the relationship between reaction dynamics and solvation structure in clusters of related cyano-aromatics. Less

本研究项目旨在通过对含有芳香族发色团的溶剂化簇进行实验研究，阐明芳香族分子中的非辐射过程如何以及为何受到周围溶剂的影响。通过应用多重激光共振、质量选择光电离和超快激光光谱等多种光谱方法，取得了以下成果：1.对吖啶和9-吖啶酮的水合簇进行了研究，探索氢键网络结构基序与发色团非辐射过程之间的分子水平相关性。通过比较实验数据（电子跃迁中的带位移和荧光检测的红外光谱）与密度泛函理论计算，确定了水合物的几何形状。皮秒时间分辨测量表明，荧光寿命很大程度上取决于簇大小以及氢键位点。微观… More pic溶剂化效应已经用与紧密分布的(n, π^*)和(π, π^*)态相关的能量学来解释，这些态的特征是通过氢键转移。2.重新研究了单体S_1-S_0区域中苯簇的电子跃迁。人们发现，根据对二聚体和三聚体离子通道的各种同位素种类记录的质量选择性钻孔光谱的详细检查，需要纠正之前二十年来接受的尺寸分配。苯三聚体和四聚体提出了新的分配，解决了迄今为止报道的实验和理论结果之间的矛盾。目前的数据还提供了团簇的几何形状和激发交换相互作用的信息。3.含有9-氰基蒽的溶剂化团簇的几何结构已通过皮秒时间分辨泵浦探针损耗实现的旋转相干光谱测定。特别是，首次建立了非质子溶剂分子（例如二氧化碳、乙腈和氟仿）的结构基序，这将为讨论相关氰基芳族化合物簇中反应动力学和溶剂化结构之间的关系奠定了坚实的基础。较少的