Development of new light scattering spectroscopy for the investigation of mode coupling molecular

软性凝聚材料具有各种内部自由度的特点。这些度之间相互作用，它们之间的耦合现象在决定软材料的复杂功能中起着重要的作用。本研究的目的是建立实验方案，以揭示这些内部自由度之间耦合现象的物理机制。首先，我们成功地发展了光散射弛豫光谱技术，直接观察流体的剪切运动与液晶中取向有序参数之间的动态相互作用。揭示了染料分子在增强光学克尔效应中的作用。应用布朗马达的思想分析了强化机理。显示转动弛豫的宽带光谱现在可以用于各种软性络合物系统。其次，我们将光学拍频布里渊光谱技术应用于分子弛豫的直接观察。由热涨落激发的声子传播与其他内部自由度相互作用，如分子缔合。然后，声子光谱被它们的运动调制，新的准弹性分量出现。我们成功地观察到了一些有机液体的这种山组分。在研究中进一步改进了布里渊光谱，可以观察到声子共振现象，对声子速度的测量精度为0.01%。利用FFT技术实现了TE的快速测量，并对液体中的耦合粘度进行了定量估算。布里渊散射技术和毛细波双折射方法的结合使我们能够唯一地确定耦合粘度以及剪切和旋转参数。

Soft condensed materials are characterized by their various kinds of internal degrees of freedom. The degrees interact each other and the coupling phenomena between them play important role in determining the complex function of the soft materials. The purpose of this study is to establish the experimental scheme to reveal the physical mechanism of the coupling phenomenon among these internal degrees of freedom.First, we successfully developed the light scattering relaxation spectroscopy technique to directly observe dynamic interaction between the shear motion of fluid and the orientational order parameter in liquid crystals. The role of the dye molecules in enhancing the optical Kerr effect is revealed. The idea of the Brownian motor was applied oanalyze the enhancing mechanism. The wideband spectra showing the rotational relaxation can be now available for various kinds of soft complex systems.Second, We applied the optical beating Brillouin spectroscopy technique to the direct observation of the molecular relaxation. Phonons excited by the thermal fluctuation propagate interacting the other internal degrees of freedom such as the molecular association. The phonon spectrum is then modulated by their motion and the new quasi-elastic component appears. We successfully observed this Mountain component for some organic liquid. The Brillouin spectroscopy is further improved in the study and we can observe the phonon resonance phenomenon giving 0.01 % accuracy in determining the phonon velocity. Te rapid measurement with FFT technique was also realized.Finally, we carried out the quantitative estimation of the coupling viscosity in liquids. Combination of the Brillouin scattering technique and the capillary wave birefringence method enables us to uniquely determine the coupling viscosity as well as the shear and rotational parameters.