From boiling point to glass transition temperature: transport coefficients in molecular liquids follow three-parameter scaling.
From boiling point to glass transition temperature: transport coefficients in molecular liquids follow three-parameter scaling.
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DOI：
10.1103/physreve.86.041507
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发表时间：
2012-04
期刊：
影响因子：
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通讯作者：
B. Schmidtke;N. Petzold;R. Kahlau;M. Hofmann;E. Rössler
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文献类型：
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作者：
B. Schmidtke;N. Petzold;R. Kahlau;M. Hofmann;E. Rössler
玻璃化转变现象是凝聚态物理学中一个尚未解决的问题。其突出的特点，超Arrhenius温度依赖性的输运系数，仍然是一个挑战，要在整个温度范围内进行描述。对于一系列分子玻璃形成剂，我们结合了从介电光谱和动态光散射收集的τ（T），覆盖范围为10（-12）s < τ（T）< 10（2）s。用活化能E（T）描述动力学，我们区分了由具有恒定活化能E（∞）的阿克里先乌斯定律表征的高温区域和E（coop）（T）E（T）-E（∞）在冷却时呈指数增加的低温区域。引入了一个标度，具体地说是E（coop）（T）/E（∞）[比例] exp[-λ（T/T（A）-1）]，其中λ是脆性参数，T（A）是与E（∞）成比例的参考温度。为了描述τ（T），还必须指定尝试时间τ（∞）。因此，描述高温状态的单个相互作用参数E（∞）与λ一起控制低温合作动力学的温度依赖性。
The phenomenon of the glass transition is an unresolved problem in condensed matter physics. Its prominent feature, the super-Arrhenius temperature dependence of the transport coefficients, remains a challenge to be described over the full temperature range. For a series of molecular glass formers, we combined τ(T) collected from dielectric spectroscopy and dynamic light scattering covering a range 10(-12) s < τ(T) < 10(2) s. Describing the dynamics in terms of an activation energy E(T), we distinguish a high-temperature regime characterized by an Arrhenius law with a constant activation energy E(∞) and a low-temperature regime for which E(coop)(T) ≡ E(T)-E(∞) increases exponentially while cooling. A scaling is introduced, specifically E(coop)(T)/E(∞) [proportionality] exp[-λ(T/T(A)-1)], where λ is a fragility parameter and T(A) a reference temperature proportional to E(∞). In order to describe τ(T) still the attempt time τ(∞) has to be specified. Thus, a single interaction parameter E(∞) describing the high-temperature regime together with λ controls the temperature dependence of low-temperature cooperative dynamics.