Institute of Automation and Electrometry, Russian Academy of Sciences, Novosibirsk 630090, Russia.
J Chem Phys. 2011 Oct 7;135(13):134510. doi: 10.1063/1.3645196.
Here, we studied Rayleigh-Brillouin light scattering in ten different glass-forming liquids (α-picoline, toluene, o-toluidine, ethanol, salol, glycerol, dibutyl phthalate, o-terphenyl, propylene carbonate, and propylene glycol). For each of these liquids it was found that the Landau-Placzek ratio is in a good agreement with the theory at high temperatures and significantly exceeds the theoretical prediction below a certain temperature. Transition between the two temperature regimes occurs near T(A), where T(A) is crossover point from an Arrhenius-like to a non-Arrhenius behavior for the α-relaxation time dependence on temperature. Increase of the Landau-Placzek ratio relative to the theoretical prediction below T(A) seems to be the universal feature of glass-formers. We suggest that formation of locally favored structures in liquids below T(A) causes observed excess of the Landau-Placzek ratio.
在这里，我们研究了十种不同的玻璃形成液体（α-皮考啉、甲苯、邻甲苯胺、乙醇、水杨酸甲酯、甘油、邻苯二甲酸二丁酯、邻三联苯、碳酸丙烯酯和丙二醇）中的瑞利-布里渊光散射。对于这些液体中的每一种，我们发现朗道-普拉克兹比在高温下与理论非常吻合，而在低于一定温度时则显著超过理论预测。这两种温度区域之间的转变发生在 T(A)附近，其中 T(A)是 α-松弛时间对温度的依赖关系从阿伦尼乌斯行为到非阿伦尼乌斯行为的交叉点。在 T(A)以下，朗道-普拉克兹比相对于理论预测的增加似乎是玻璃形成体的普遍特征。我们认为，在 T(A)以下的液体中形成局部有利结构导致了观察到的朗道-普拉克兹比的过剩。
