Diezemann Gregor, Böhmer Roland
Institut für Physikalische Chemie, Universität Mainz, 55099 Mainz, Federal Republic of Germany.
J Chem Phys. 2006 Jun 7;124(21):214507. doi: 10.1063/1.2202351.
Several fluctuation-dissipation relations are investigated for a simple free-energy landscape model designed to describe the primary relaxation in supercooled liquids. The calculations of the response and of the correlation functions are performed for a quench from a high temperature to a low temperature. In the model, all dynamical quantities reach equilibrium after long times, but for times shorter than the re-equilibration time they do not exhibit time-translational invariance and the fluctuation-dissipation theorem is violated. Two measures for these violations are considered. One such measure is given by the slope in a plot of the integrated response versus the correlation function and another one by the so-called fluctuation-dissipation ratio. It is found that these measures do not coincide and furthermore are not independent of the dynamical variable considered in the calculation. We propose to determine the fluctuation-dissipation ratio experimentally via measurements of the deuteron spin-lattice relaxation rate and the dielectric loss.
针对一个旨在描述过冷液体中主要弛豫过程的简单自由能景观模型，研究了几种涨落 - 耗散关系。响应函数和关联函数的计算是针对从高温到低温的猝灭情况进行的。在该模型中，所有动力学量在长时间后达到平衡，但在短于重新平衡时间的情况下，它们不表现出时间平移不变性，并且涨落 - 耗散定理被违反。考虑了两种衡量这些违反情况的方法。一种这样的衡量方法由积分响应与关联函数的绘图中的斜率给出，另一种由所谓的涨落 - 耗散比给出。结果发现，这些衡量方法不一致，而且还与计算中考虑的动力学变量有关。我们建议通过测量氘核自旋 - 晶格弛豫率和介电损耗来实验确定涨落 - 耗散比。
