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arXiv 0908.0683cond-mat.soft
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粘性液体中的密度标度和动力学关联

Density Scaling and Dynamic Correlations in Viscous Liquids

D. Fragiadakis, R. Casalini, C. M. Roland

摘要:

我们使用最近提出的方法[Berthier L.; Biroli G.;布绍; Cipelletti L.; El Masri D.; L'Hote D.;拉迪厄·F.;皮尔诺·M Science 2005,310,1797.]以从线性介电响应函数的导数获得4点动态关联函数的近似。对于四种液体在一定的压力范围内,我们发现,动态相关的分子,Nc的数量,只取决于弛豫时间的大小,独立的温度和压力。这一结果与弛豫时间恒定时弛豫色散形状的不变性和弛豫时间的密度标度性质一致,并意味着Nc也符合相同的标度行为。对于碳酸亚丙酯和salol Nc成为常数与方法的Arcadius政权,与预期的分子间非合作松弛的统一的值一致。

英文摘要:

We use a recently proposed method [Berthier L.; Biroli G.; Bouchaud J.P.; Cipelletti L.; El Masri D.; L'Hote D.; Ladieu F.; Pierno M. Science 2005, 310, 1797.] to obtain an approximation to the 4-point dynamic correlation function from derivatives of the linear dielectric response function. For four liquids over a range of pressures, we find that the number of dynamically correlated molecules, Nc, depends only on the magnitude of the relaxation time, independently of temperature and pressure. This result is consistent with the invariance of the shape of the relaxation dispersion at constant relaxation time and the density scaling property of the relaxation times, and implies that Nc also conforms to the same scaling behavior. For propylene carbonate and salol Nc becomes constant with approach to the Arrhenius regime, consistent with the value of unity expected for intermolecularly non-cooperative relaxation.

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