AI 中文总结
本研究对比了分子玻璃与同相互作用势、同制备方案的原子型玻璃的振动等性质，揭示了刚性分子约束对玻璃力学和振动特性的影响，为相关研究提供了新认知。
AI 中文摘要
近年来，在阐明结构玻璃振动性质的统计物理学方面已取得显著进展。尽管与科学和技术相关的许多实际玻璃是分子玻璃，但大多数关于结构玻璃力学和振动性质的计算研究采用的是简单的原子型玻璃形成模型。因此，刚性分子约束对玻璃力学和振动性质的影响在很大程度上仍未被探索。在本研究中，我们直接比较了分子计算机玻璃与具有相同分子间相互作用势、采用相同制备方案构建的原子型模型的性质。我们发现，与原子型玻璃相比，分子玻璃具有更高程度的力学无序性，更大的介观关联长度，同时每个原子对应的软质类局域振动数量更少。我们通过考虑刚性分子约束诱导的有效自由度减少来解释这些差异。我们还发现，在受驱动玻璃态固体中承载塑性变形的非线性塑性模式，在分子玻璃中与体积应变的耦合要强得多。文中还讨论了未来的研究方向。
英文摘要
Recent years have seen substantial progress in elucidating the statistical physics of the vibrational properties of structural glasses. Although many real-world glasses relevant for science and technology are molecular, the majority of computational studies concerning the mechanical and vibrational properties of structural glasses employ simple atomistic glass-forming models. Thus, the effects of stiff molecular constraints on mechanical and vibrational glass physics remain largely unexplored. In this work, we directly compare the properties of a molecular computer glass with those of an atomistic model featuring the same inter-molecular interaction potential, and created using the same formation protocol. We find that the molecular glass features a higher degree of mechanical disorder, with larger mesoscopic correlation lengths, while at the same time it hosts a lower number of soft, quasilocalized vibrations per atom -- compared to the atomistic glass. We rationalize these differences by accounting for the reduction in the effective number of degrees of freedom induced by the stiff molecular constraints. We additionally find that nonlinear plastic modes --- that carry plastic deformation in driven glassy solids --- couple much more strongly to volumetric strains in the molecular glass. Future research directions are discussed.
Comments11 pages, 8 figures
