The failure of the Classical Nucleation Theory at low temperatures resolved
The failure of the Classical Nucleation Theory at low temperatures resolved
复制标题
经典成核理论在低温下的失败得到解决
DOI：
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发表时间：
2019
期刊：
影响因子：
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通讯作者：
Edgar Dutra Zanotto
中科院分区：
文献类型：
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作者：
D. Cassar;A. Serra;O. Peitl;A. M. Rodrigues;Edgar Dutra Zanotto
几十年来，关于玻璃形成物质中晶体形核动力学的相关观察一直是一个激烈的争论问题。经典形核理论(CNT)不能描述在最大形核速率温度以下的均匀晶体形核速率与温度的关系。据报道，有几种玻璃形成物质发生了这种失效，这种失效被称为成核“破裂”。对于这种明显的断裂，文献中已经提出了一些合理的解释，然而，最简单的假设从未被检验过：这种断裂是尚未达到稳定状态的成核数据集的副产品。在这项工作中，我们通过彻底分析新的和公布的过冷Li2Si2O5、BaSi2O5、Na4CaSi3O9和Na2Ca2Si3O9液体的成核数据来检验这一假设，只使用已经达到(可能)稳态条件的数据集。为此，我们使用了三个约束条件：i)在同一批玻璃中测量成核和扩散数据，并对每一批进行单独分析；ii)仅使用通过稳态状态检验的成核率数据进行分析；iii)计算并考虑不确定度和回归置信带。通过这一策略，我们证明了所谓的成核破裂确实是一种实验文物！这一结果结束了长达40年的困境，并证实了使用碳纳米管来分析晶体成核率。
A relevant observation about crystal nucleation kinetics in glass-forming substances has been a matter of intense debate for several decades. The Classical Nucleation Theory (CNT) allegedly fails to describe the temperature dependence of the homogeneous crystal nucleation rates below the temperature of maximum nucleation rate. This failure was reported for several glass-forming substances and is known as nucleation "breakdown". Some reasonable explanations for this apparent break have been advanced in the literature, however, the simplest hypothesis has never been tested: that this break is a byproduct of nucleation datasets that have not reached the steady-state regime. In this work, we tested this hypothesis by thoroughly analyzing new and published nucleation data for supercooled Li2Si2O5, BaSi2O5, Na4CaSi3O9, and Na2Ca2Si3O9 liquids, using only datasets for which steady-state conditions (likely) have been reached. For that purpose, we used three restraining conditions: i) Nucleation and diffusion data were measured in the same glass batch, and each batch was individually analyzed; ii) only nucleation rate data that passed a steady-state regime test were used in the analysis; iii) the uncertainty and regression confidence bands were computed and considered. With this strategy, we proved that the alleged nucleation break is indeed an experimental artifact! This result ends a four decade-old dilemma and corroborates the use of CNT for analyses of crystal nucleation rates.