Grzybowski A, Koperwas K, Paluch M
Institute of Physics, University of Silesia in Katowice, 41-500 Chorzów, Poland.
Rep Prog Phys. 2024 Jul 3;87(8). doi: 10.1088/1361-6633/ad569d.
Molecular Dynamics (MD) simulations of glass-forming liquids play a pivotal role in uncovering the molecular nature of the liquid vitrification process. In particular, much focus was given to elucidating the interplay between the character of intermolecular potential and molecular dynamics behaviour. This has been tried to achieve by simulating the spherical particles interacting via isotropic potential. However, when simulation and experimental data are analysed in the same way by using the density scaling approaches, serious inconsistency is revealed between them. Similar scaling exponent values are determined by analysing the relaxation times and pVT data obtained from computer simulations. In contrast, these values differ significantly when the same analysis is carried out in the case of experimental data. As discussed thoroughly herein, the coherence between results of simulation and experiment can be achieved if anisotropy of intermolecular interactions is introduced to MD simulations. In practice, it has been realized in two different ways: (1) by using the anisotropic potential of the Gay-Berne type or (2) by replacing the spherical particles with quasi-real polyatomic anisotropic molecules interacting through isotropic Lenard-Jones potential. In particular, the last strategy has the potential to be used to explore the relationship between molecular architecture and molecular dynamics behaviour. Finally, we hope that the results presented in this review will also encourage others to explore how 'anisotropy' affects remaining aspects related to liquid-glass transition, like heterogeneity, glass transition temperature, glass forming ability, etc.
玻璃形成液体的分子动力学（MD）模拟在揭示液体玻璃化过程的分子本质方面起着关键作用。特别是，人们非常关注阐明分子间势的特性与分子动力学行为之间的相互作用。这一直试图通过模拟经由各向同性势相互作用的球形粒子来实现。然而，当使用密度标度方法以相同方式分析模拟数据和实验数据时，发现它们之间存在严重的不一致。通过分析从计算机模拟获得的弛豫时间和pVT数据确定了相似的标度指数值。相比之下，在实验数据的情况下进行相同分析时，这些值有显著差异。如本文所详细讨论的，如果将分子间相互作用的各向异性引入MD模拟中，就可以实现模拟结果与实验结果之间的一致性。在实践中，这已经通过两种不同的方式实现：（1）使用盖伊 - 伯尔尼型各向异性势，或（2）用通过各向同性的勒纳德 - 琼斯势相互作用的准真实多原子各向异性分子取代球形粒子。特别是，最后一种策略有潜力用于探索分子结构与分子动力学行为之间的关系。最后，我们希望本综述中呈现的结果也将鼓励其他人探索“各向异性”如何影响与液 - 玻璃转变相关的其他方面，如非均匀性、玻璃化转变温度、玻璃形成能力等。
