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arXiv 1412.7486cond-mat.softphysics.bio-ph
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非惰性障碍物拥挤介质中的非普适示踪剂扩散

Non-universal tracer diffusion in crowded media of non-inert obstacles

Surya K. Ghosh, Andrey G. Cherstvy, Ralf Metzler

备注：
12 pages, 9 figues, RevTeX4
发表信息：
Phys. Chem. Chem. Phys. 17, 1847 (2015)
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摘要：

我们研究了示踪粒子的扩散，它在连续空间中移动之间的晶格排除体积，不动的非惰性障碍物。特别是，我们分析了示踪剂-障碍物相互作用的强度和拥挤的体积占用率如何改变示踪剂的扩散运动。从细节的示踪剂扩散模式之间的捕获状态绑定到障碍物和散装扩散的分区，我们研究的示踪剂在拥挤的晶格中的本地化程度。我们研究了示踪剂扩散的性质，在合奏和时间平均均方位移，捕获时间分布，时间平均均方位移的幅度变化，和扩散示踪剂的非高斯参数。我们得出结论，示踪剂障碍物的吸附和绑定触发瞬态异常扩散。从一个非常狭窄的传播记录个人的时间平均轨迹，我们排除连续型随机游走过程作为基础的物理模型的示踪剂扩散在我们的系统。对于中等示踪剂拥挤的吸引力的运动被发现是完全遍历的，而在更强的吸引力强度的合奏和时间平均均方位移之间的瞬态差距发生。我们还把我们的研究结果的角度来看，从实验的单粒子跟踪和模拟的标记示踪剂在密集拥挤的悬浮液中的扩散的结果。我们的研究结果对在活细胞和其他结构液体内高度拥挤的环境中化学成分的扩散，运输和传播具有影响。

英文摘要：

We study the diffusion of a tracer particle, which moves in continuum space between a lattice of excluded volume, immobile non-inert obstacles. In particular, we analyse how the strength of the tracer-obstacle interactions and the volume occupancy of the crowders alter the diffusive motion of the tracer. From the details of the partitioning of the tracer diffusion modes between trapping states when bound to obstacles and bulk diffusion, we examine the degree of localisation of the tracer in the lattice of crowders. We study the properties of the tracer diffusion in terms of the ensemble and time averaged mean squared displacements, the trapping time distributions, the amplitude variation of the time averaged mean squared displacements, and the non-Gaussianity parameter of the diffusing tracer. We conclude that tracer-obstacle adsorption and binding triggers a transient anomalous diffusion. From a very narrow spread of recorded individual time averaged trajectories we exclude continuous type random walk processes as the underlying physical model of the tracer diffusion in our system. For moderate tracer-crowder attraction the motion is found to be fully ergodic, while at stronger attraction strength a transient disparity between ensemble and time averaged mean squared displacements occurs. We also put our results into perspective with findings from experimental single-particle tracking and simulations of the diffusion of tagged tracers in dense crowded suspensions. Our results have implications for the diffusion, transport, and spreading of chemical components in highly crowded environments inside living cells and other structured liquids.

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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