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首页> 外文期刊>Journal of Non-Crystalline Solids: A Journal Devoted to Oxide, Halide, Chalcogenide and Metallic Glasses, Amorphous Semiconductors, Non-Crystalline Films, Glass-Ceramics and Glassy Composites >Fast relaxation processes in glasses as revealed by depolarized light scattering
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Fast relaxation processes in glasses as revealed by depolarized light scattering

机译：通过去偏振光散射揭示的玻璃中的快速松弛过程

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Applying tandem-Fabry-Perot interferometry together with a double monochromator, depolarized light scattering spectra were measured in order to investigate the fast relaxation processes and vibrations in molecular, ionic and polymeric glasses in the 1-5000 GHz range covering temperatures from the glass transition temperature Tg down to some 10 K. In addition to the boson peak, the spectra reveal quasi-elastic contributions that we attribute to (i) a nearly constant loss in the frequency range below congruent to 10 GHz and (ii) a power-law contribution with positive exponent alpha at higher frequencies. In the majority of glasses the latter may be attributed to thermally activated dynamics in asymmetric double well potentials as previously found for the light scattering spectra in silica. Following the Gilroy-Phillips model the exponent a shows a master curve as a function of T/V-0 for the various glasses, where V-0 specifies the width of the exponential distribution of barriers g(V), i.e., g(V) proportional to exp(-V/V-0). The parameter V-0 is found to be similar to T-g/2 in most cases. The relative strength of the dynamics in asymmetric double well potentials and the nearly constant loss contribution is different in the glasses studied. (C) 2007 Elsevier B.V. All rights reserved.
机译：将串联法布里-珀罗干涉仪与双单色仪一起使用，测量了去偏振光散射光谱，以研究分子，离子和聚合物玻璃在1-5000 GHz范围内的快速弛豫过程和振动，该温度涵盖了从玻璃化转变温度开始的温度Tg降低到大约10K。除了玻色子峰，光谱还揭示了准弹性贡献，我们可以将其归因于（i）低于10 GHz的频率范围内几乎恒定的损耗，以及（ii）幂律贡献在较高频率下具有正指数α。在大多数玻璃中，后者可能归因于不对称双阱电势中的热活化动力学，如先前在二氧化硅中的光散射光谱所发现的。根据吉尔罗伊-菲利普斯（Gilroy-Phillips）模型，指数a显示了作为各种玻璃的T / V-0的函数的主曲线，其中V-0指定了势垒g（V）的指数分布的宽度，即g（V ）与exp（-V / V-0）成正比。发现在大多数情况下，参数V-0与T-g / 2相似。在所研究的玻璃中，非对称双阱势中动力学的相对强度和几乎恒定的损耗贡献是不同的。 （C）2007 Elsevier B.V.保留所有权利。

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