Investigation of Electronic-State Dependence of Photoreaction

分子的光反应在很大程度上取决于激发态的性质。研究激发态波函数的特征和光反应之间的关系是很有趣的，因为这样的研究阐明了电子的微观运动对所产生的光反应的影响。本课题主要利用发射光谱的方法研究光反应的电子态依赖性。为了进行这项研究，我们制作了一个发射分光光度计。我们买了探测端的光谱仪，探测器和控制器。在此之前，我们已经购买了激发侧的光谱仪和灯。新分光光度计的灵敏度大大高于旧分光光度计，大大提高了研究效率。我们观察了水杨醛相关分子的第一和第二激发态的荧光，并讨论了质子转移反应的电子态依赖性。从理论研究中，我们发现了波函数节点对有机分子光反应的影响。此外，我们还研究了水杨醛相关分子在三态和离子态下的质子转移反应，2 -（2'-羟基苯基）苯并噻唑、2-（2'-羟基苯基）苯并唑和2,2'-联吡啶-3,3'-二醇在最低三态下的质子转移反应，溶剂对类胡萝卜素松弛过程的影响，以及类胡萝卜素表现出双发射特性的原因。长冈教授被选为日本化学学会的“Kagaku No Frontier VII”和“第六届青年学者讲座”。他还在美国化学学会出版的《物理化学杂志》上发表了一篇特邀论文（1991年第95卷，第10229-10235页）。

The photoreaction of molecules depends largely on the nature of the excited state. It is interesting to study the relationship between the characteristics of the wave function of the excited state and the photoreaction, because such a study clarifies the effect of microscopic motion of electrons on the resultant photoreaction. The purpose of this project is to study the electronic-state dependence of photoreactions mainly by means of the emission spectroscopy. In order to perform this study, we made an emission spectrophotometer. We bought the spectrometer of the detection-side, the detector, and the controller. Previously, we had already bought the spectrometer of the excitation-side and the lamp. The sensitivity of the new spectrophotometer is much larger than the old one and the efficiency of the study was enhanced very much. We observed the fluorescence from the first and second excited singlet states of the related molecules of salicylaldehyde and discussed the electronic-state dependence of the proton transfer reaction. From theoretical studies, we found the effect of the node of the wave function on the photoreaction of organic molecules. Furthermore, we studied the proton transfer reactions in the triplet state and the ionic state of the related molecules of salicylaldehyde, the proton transfer in the lowest triplet states of 2-(2'-hydroxyphenyl)benzothiazole, 2-(2'-hydroxyphenyl)benzoxazole, and 2,2'-bipyridyl-3,3'-diol, the solvent effect on the relaxation processes of carotenoids showing dual emissive characteristics, the reason for the weak phosphorescence of pyridines. S. Nagaoka was chosen as 'Kagaku No Frontier VII' and 'the 6th Young Scholar Lecture' of the Chemical Society of Japan. He also wrote an invited paper in The Journal of Physical Chemistry published from the American Chemical Society (Vol. 95, pp. 10229-10235, 1991).