Energy landscapes for diffusion: Analysis of cage-breaking processes
Energy landscapes for diffusion: Analysis of cage-breaking processes
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DOI：
10.1063/1.2992128
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发表时间：
2008-10-28
影响因子：
4.4
通讯作者：
Wales, David J.
中科院分区：
文献类型：
--
作者：
de Souza, Vanessa K.;Wales, David J.
二元Lennard-Jones系统存在着宽谱的势能垒。在这里，我们将研究与长期扩散相关的障碍和打破笼子的重排。单步破笼过程，遵循高障碍的路线，被确定，并考虑不同的方法和标准来定义一个破笼过程。我们研究在何种程度上打破笼子内的能源景观的描述是一个长期的扩散的描述。这一描述包括确定被逆转的笼子破裂，以及那些有利于长期扩散的笼子破裂。在低温下，扩散是充分描述生产笼打破，或考虑所有笼打破和占的逆转的影响。为了估计扩散常数，我们只需要一个笼子打破的均方位移，一个笼子打破的平均等待时间，和反向笼子打破的数量的措施。笼子打破可以可视化内的潜在能源景观使用断开图，我们比较了使用生产性笼子打破与以前的定义的“巨型基地”或“元基地”。2008年美国物理学会。[DOI：10.1063/1.2992128]
A wide spectrum of potential energy barriers exists for binary Lennard-Jones systems. Here we examine the barriers and cage-breaking rearrangements that are pertinent to long-term diffusion. Single-step cage-breaking processes, which follow high-barrier routes, are identified, and different methods and criteria for defining a cage-breaking process are considered. We examine the extent to which a description of cage-breaking within the energy landscape is a description of long-term diffusion. This description includes the identification of cage-breaks that are reversed, and those that are productive towards long-term diffusion. At low temperatures, diffusion is adequately described by productive cage-breaks, or by considering all cage-breaks and accounting for the effect of reversals. To estimate the diffusion constant we require only the mean square displacement of a cage-break, the average waiting time for a cage-break, and a measure of the number of reversed cage-breaks. Cage-breaks can be visualized within the potential energy landscape using disconnectivity graphs, and we compare the use of productive cage-breaks with previous definitions of "megabasins" or "metabasins." (C) 2008 American Institute of Physics. [DOI: 10.1063/1.2992128]