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

通过对系统中引入的染料分子进行各种光学测量，无序系统中的超快动力学已得到了广泛的研究。已经发现，在室温下的溶液中，电子地面和激发态之间的光学脱位出现在飞秒的时间尺度上，反映了周围原子的动力学，并且无法通过简单的指数衰减来描述dephasing过程。在这项研究中，不连贯的光子回声和二阶光学过程研究了乙醇中β-胡萝卜素的光学去序列。我们发现，即使在50 k的时间范围内，这些时间范围也发生在飞秒的时间尺度上。这些时间域和频域测量由电子 - phonon相互作用的动态模型分析。由于该模型很好地再现了光子回声和二阶光学过程的结果，因此我们认为具有线性电子 - phonon相互作用的动态模型是描述该系统中超快驱动过程的良好近似值。另外，β-胡萝卜素分子的去率过程近似为缓慢的调节状态。从绝热势的角度来看，E_ <lr>/ω0= 8的获得值表明，对于β-胡萝卜素分子中的长共轭系统，电子 - 光子相互作用相对较强。飞秒时间尺度中的DEPHASENT基本上来自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。