The electron-phonon interaction in liquid investigated by near-resonantly excited Ramen scattering spectra

通过近共振激发拉曼散射光谱研究液体中的电子-声子相互作用

• 批准号: 11640315
• 负责人: WATANABE Junji
• 金额: $ 2.3万
• 依托单位: Osaka University
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for Scientific Research (C)
• 财政年份: 1999
• 资助国家: 日本
• 起止时间: 1999 至 2000
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-11640315/
• 关键词: optical dephasing; secondary radiation; Raman scattering; electron-phonon interaction; β-carotene

The ultrafast dynamics in disordered system has been extensively investigated by various optical measurements on dye molecules introduced into the system. It has been found that, in solutions at room temperature, the optical dephasing between the electronic ground and excited states occurs on the time scale of femtoseconds reflecting the dynamics of surrounding atoms and that the dephasing process cannot be described by a simple exponential decay. In this research, the optical dephasing of β-carotene in ethanol has been investigated by incoherent photon echo and the second-order optical processes. We found that the dephasing occured on the time scale of femtoseconds even at 50 K.These time-domain and frequency-domain measurements are analyzed by the dynamical model for the electron-phonon interaction. Since results of photon echo and second-order optical process are well reproduced by the model, we consider that the dynamical model with linear electron-phonon interaction is a good approximation for describing the ultrafast dephasing process in this system. In addition, the dephasing process of β-carotene molecule is approximately characterized by the slow modulation regime. From the viewpoint of adiabatic potential, the obtained value of E_<LR>/ω0=8 indicates that the electron-phonon interaction is relatively strong for the long conjugated system in β-carotene molecule. The dephasing in femtosecond time scale essentially comes from this relatively strong coupling

无序体系中的超快动力学已经通过对染料分子的各种光学测量得到了广泛的研究。人们发现，在室温下的溶液中，电子基态和激发态之间的光学退相发生在飞秒的时间尺度上，反映了周围原子的动力学，并且退相过程不能用简单的指数衰减来描述。本文利用非相干光子回波和二阶光学过程研究了β-胡萝卜素在乙醇中的光学退相。我们发现，失相发生在飞秒的时间尺度上，即使在50 K.这些时域和频域的测量分析的动力学模型的电子-声子相互作用。由于该模型很好地再现了光子回波和二阶光学过程的结果，我们认为线性电子-声子相互作用动力学模型是描述该系统超快退相过程的一个很好的近似。此外，β-胡萝卜素分子的失相过程近似地具有慢调制区的特征。从绝热势的观点看，<LR>β-胡萝卜素分子中长共轭体系的电子-声子相互作用较强，E/ω0=8。飞秒时间尺度上的退相本质上来自于这种相对较强的耦合

项目成果

Shuichi Kinoshita: "Femtosecond optical Kerr effect measurement on initial process of liquid dynamics"Journal of Luminescence. 87-89. 706-708 (2000)

Shuichi Kinoshita：“液体动力学初始过程的飞秒光学克尔效应测量”发光杂志。

Junji Watanabe: "Relation between Stokes and anti-Stokes low-frequency light scattering in liquid carbon disulfide"Chemical Physics Letters. 333. 113-118 (2001)

渡边淳二：《液态二硫化碳中斯托克斯与反斯托克斯低频光散射的关系》《化学物理快报》。

Junji Watanabe: "Discrepancy in response functions obtained from Stokes and anti-Stokes low-frequency light scattering in liquid"Journal of Luminescence. (2000)

Junji Watanabe：“液体中斯托克斯和反斯托克斯低频光散射获得的响应函数的差异”发光杂志。

J.Watanabe, R.Nakamura, A.Ohyama and J.Nakahara: "Optical Dephasing of β-Carotene in Photon Echo and Second-Order Optical Processes"Carotenoid Science. (in press).

J. Watanabe、R. Nakamura、A. Ohyama 和 J. Nakahara：“光子回波和二阶光学过程中 β-胡萝卜素的光学相移”类胡萝卜素科学（正在出版）。

S.Kinoshita, Y.Kai, Y.Watanabe and J.Watanabe: "Femtosecond optical Kerr effect measurement on initial process of liquid dynamics"Journal of Luminescence. 87-89. 706-708 (2000)

S.Kinoshita、Y.Kai、Y.Watanabe 和 J.Watanabe：“液体动力学初始过程的飞秒光学克尔效应测量”发光杂志。