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arXiv 0902.4078cond-mat.softcond-mat.stat-mech
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过冷液体动力学交叉区结构弛豫时间的波数依赖性

Wavenumber dependence of the structural relaxation time in the crossover regime of supercooled liquid dynamics

Sarika Maitra Bhattacharyya, Biman Bagchi, Peter G. Wolynes

摘要:

随着液体逐渐过冷一个有趣的削弱波数($q$)的依赖性的结构弛豫时间$τ(q)$在大的q限制观察到在实验和模拟研究。无论是连续的布朗扩散动力学还是不连续的激活事件都不能单独解释反常的波数依赖性。在这里,我们使用我们最近开发的理论,该理论统一了连续动力学的模式耦合理论(MCT)和将激活的不连续运动视为成核(瞬子)过程的随机一级跃迁理论(RFOT),以理解密度的波数依赖性弛豫。预测的平滑变化的机制,从扩散激活,在交叉制度的松弛,是波矢量依赖性,并最终负责次二次,几乎线性,$q$依赖的松弛时间。

英文摘要:

As a liquid is progressively supercooled an intriguing weakening of the wavenumber ($q$) dependence of the structural relaxation time $τ(q)$ in the large q limit is observed both in experiments and simulation studies. Neither the continuous Brownian diffusive dynamics nor the discontinuous activated events can alone explain the anomalous wavenumber dependence. Here we use our recently developed theory that unifies the mode coupling theory (MCT) for continuous dynamics and the random first order transition theory (RFOT) treatment of activated discontinuous motion as a nucleation (instanton) process, to understand the wavenumber dependence of density relaxation. The predicted smooth change in mechanism of relaxation from diffusive to activated, in the crossover regime, is wavevector dependent and is eventually responsible for sub-quadratic, almost linear, $q$ dependence of the relaxation time.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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