Charge-transfer State Formation in Supercritical Fluids

本研究包括以下四个项目：1。4-N， n -二甲氨基苯并腈（DMABN）的拉曼光谱形成分子内电荷转移（CT）状态的分子的CARS光谱。超临界流体中丙酮和CH_3CN的拉曼光谱。超临界流体中电荷转移态的形成。本研究最初的目的是获得DMABN CT态的拉曼光谱，以验证苯和二甲胺平面之间的垂直性。然而，即使使用延时共振拉曼光谱，由于背景荧光的存在，观察CT态的拉曼光谱也相当困难。然后我们尝试观察CARS光谱，由于缺乏与拉曼激发共振的合适激发态，再次失败。然而，在上述实验过程中，我们获得了超临界流体中拉曼位移和CT反应速率作为密度函数的重要信息。拉曼位移包含了振子局部环境的丰富信息，利用Buckingham微扰理论结合percusyevick积分方程对其进行了进一步分析。此外，在超临界CF_3H下确定DMABN中CT形成速率的密度依赖关系，并根据超临界溶液中的平均簇数进行解释。

The present study consists of the following four items :1. Raman spectra of 4-N,N-dimethylaminobenzonitrile (DMABN) .2. CARS spectra of molecules forming intramolecular charge-transfer (CT) state.Raman spectra of acetone and CH_3CN in supercritical fluids.4. Charge-transfer state formation in supercritical fluids.The original purpose of this study was to obtain the Raman spectrum of the CT state of DMABN to verify the perpendicularity between the benzene and the dimethylamino planes. However, even with the time-delayd resonance Raman spectroscopy, it turned out that the observation of the Raman spectra of the CT state was quite difficult due to the background fluorescence. Then we attempted to observe the CARS spectrum, again being unsuccessful because of the absence of an appropriate excited state resonant with the Raman excitation.Nevertheless, we gained important information concerning the Raman shift and the CT reaction rate in supercritical fluids as a function of density in the course of the above experiments. The Raman shift contained the rich information on the local environment for the oscillator, which was further analyzed by means of Buckingham's perturbation theory combined with the Percus-Yevick integral equation. Furthermore, the density dependence of the CT formation rate in DMABN was determined in supercritical CF_3H and interpreted in terms of the average clustering number in supercritical solutions.