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arXiv 2011.06506cond-mat.stat-mech
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玻璃自由能的数值计算方法

Numerical method for computing the free energy of glasses

H. A. Vinutha, Daan Frenkel

摘要:

我们提出了一种数值技术来计算玻璃的平衡自由能,不能准备准可逆。对于这样的系统,不能使用通过外推法估计自由能的标准技术。相反,我们使用一个程序,样本的平衡配分函数的吸引力的不同的固有结构(局部势能极小值)的系统的盆地。如果所有相关的固有结构可以在(过冷)液相中充分采样,我们的方法将是严格的。在任何有限模拟中,我们都会错过在非常低的温度下占主导地位的低能固有结构。我们发现,我们的自由能估计的Kob-Andersen玻璃是低于通过非常缓慢的冷却,即使在温度下降到三分之一的玻璃化转变温度。目前的方法可以应用于计算化学势的超稳定的玻璃质材料,并应使其溶解度的估计。

英文摘要:

We propose a numerical technique to compute the equilibrium free energy of glasses that cannot be prepared quasi-reversibly. For such systems, standard techniques for estimating the free energy by extrapolation, cannot be used. Instead, we use a procedure that samples the equilibrium partition function of the basins of attraction of the different inherent structures (local potential energy minima) of the system. If all relevant inherent structures could be adequately sampled in the (supercooled) liquid phase, our approach would be rigorous. In any finite simulation, we will miss the lower-energy inherent structures that become dominant at very low temperatures. We find that our free energy estimates for a Kob-Andersen glass are lower than those obtained by very slow cooling, even at temperatures down to one third of the glass transition temperature. The current approach could be applied to compute the chemical potential of ultra-stable glassy materials, and should enable the estimation of their solubility.

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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