Solvent-Solute Interaction in Liquid and Solid Phases of Ethanol Probed by Photon Echo Spectroscopy

用光子回波光谱法探测乙醇液相和固相中的溶剂-溶质相互作用

基本信息

批准号：
08640405
负责人：
WATANABE Junji
金额：
$ 1.41万
依托单位：
HOKKAIDO UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
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-08640405/
关键词：
Photon Echo Optical Dephasing Solvent-Solute Interaction Beta-Carotene Non-Markovian Phonon Density of States

项目摘要

The optical dephasing of dye molecules in solution has been extensively investigated by various experimental methods and it is shown that the dephasing occurs on the time scale of femtoseconds with a non-Markovian nature. Since photon echo spectroscopy is a powerful tool for investigating solvation dynamics, several groups report echo responses measured at room temperature utilizing femtoseconds laser pulses. However reports on the temperature dependence of solvation dynamics are quite limited. The investigation of temperature dependence is important because it gives detailed information about the solvation dynamics.In this research, the solvation dynamics of beta-carotene molecules in ethanol has been investigated by incoherent photon echo spectroscopy at various temperatures from 300 K to 50 K.Experimental results are analyzed based on a dynamical model for a dephasing in femtoseconds and a stochastic model for a slow energy fluctuation. Using parameter values for the dynamical model determined from fluorescence spectra, we obtain amplitude and correlation time of the slow energy fluctuation in picoseconds time scale in solid phase of ethanol. It is shown that the fast response of echo signals in femtoseconds time scale essentially comes from the relatively strong electron-phonon coupling in this system and that the slow energy fluctuation decreases the rephasing process resulting in much faster response. The incoherent photon echo probes the slow energy fluctuation in picosecond order, Which is longer than the delay time between two excitation pulses.

通过各种实验方法对溶液中染料分子的光学去序列已进行了广泛的研究，并且表明该脱位发生在具有非马克维亚性质的飞秒的时间尺度上。由于光子回声光谱是研究溶剂化动力学的强大工具，因此几个组报告了利用飞秒激光脉冲在室温下测得的回声反应。但是，有关溶剂化动力学温度依赖性的报告非常有限。温度依赖性的研究很重要，因为它提供了有关溶剂化动力学的详细信息。在这项研究中，已经通过不连贯的光子回声光谱在各种温度下通过300 K到50 K的多个温度进行了基于一个动态模型的动态模型来分析乙醇中β-胡萝卜素分子在乙醇中的溶剂化动力学。波动。使用由荧光光谱确定的动力学模型的参数值，我们在乙醇的固体相中以picseconds时间尺度获得了缓慢的能量波动的振幅和相关时间。结果表明，飞秒时间尺度中回声信号的快速响应本质上来自该系统中相对强的电子 - 音波耦合，并且缓慢的能量波动降低了转化过程，从而导致响应更快。不一致的光子回声以皮秒级探测缓慢的能量波动，比两个激发脉冲之间的延迟时间长。