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arXiv 1508.04517cond-mat.soft
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密度反常液体中的动力学和瞬时简正模

Dynamics and instantaneous normal modes in a liquid with density anomalies

Massimo Pica Ciamarra, Peter Sollich

摘要:

研究了过冷液体的动力学特征与其势能面之间的关系,重点研究了具有密度异常的模型液体。我们认为,在固定的温度下,对状态点具有不同的密度,但相同的扩散常数,并发现令人惊讶的是,他们有相同的动力学特征,在所有的长度和时间尺度。这是由他们的均方位移和他们的自我-中间散射函数在不同的波矢崩溃。然后,我们调查的功能的能量景观的密度变化,并建立具有相同的扩散常数的状态点有不同的景观。特别是,我们发现的分数瞬时正常模式连接不同的能量最小值和扩散常数之间的相关性,但不像在其他系统中,这两个数量是不是在一对一的相互对应,显示额外的景观功能必须在确定的扩散常数相关。

英文摘要:

We investigate the relation between the dynamical features of a supercooled liquid and those of its potential energy landscape, focusing on a model liquid with density anomalies. We consider, at fixed temperature, pairs of state points with different density but the same diffusion constant, and find that surprisingly they have identical dynamical features at all length and time scales. This is shown by the collapse of their mean square displacements and of their self--intermediate scattering functions at different wavevectors. We then investigate how the features of the energy landscape change with density, and establish that state points with equal diffusion constant have different landscapes. In particular, we find a correlation between the fraction of instantaneous normal modes connecting different energy minima and the diffusion constant, but unlike in other systems these two quantities are not in one--to--one correspondence with each other, showing that additional landscape features must be relevant in determining the diffusion constant.

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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