Nucleation, glass formation, and phase behavior in supercooled liquids

液态是我们理解物质的一个持久的挑战来源。 即使是最简单的经典液体，也是一个稠密、无序、强相互作用的多体系统。 因此，液体向我们展示了丰富的行为和令人生畏的复杂性，特别是在分子尺度上。 在液态物理学中，一些最重要和最令人困惑的未决问题发生在过冷液体中。在玻璃化转变时无定形固体形成的性质是公开辩论的持续来源。 类似地，从液态结晶固体的成核也没有完全理解;例如，对于许多重要的系统，理论以定量准确度预测晶体成核速率的能力仍然很差。 虽然这些问题中有许多是基本性质的，但实际应用却比比皆是。例如，金属合金的玻璃形成能力是一个具有积极商业兴趣的领域，新公司制造非晶金属产品，如高尔夫球杆和飞机部件。 胶体液体也是一个爆炸性增长的领域，我们对经典分子液体的理解可以直接转移到胶体液体。 在过冷液体的背景下，一些不同的和复杂的现象收敛：亚稳相的热力学;粘性液体的复杂的传输特性;和晶体成核的非平衡动力学。该提案描述了一项研究计划，以调查过冷液体的性质，并有意关注这些现象相互交织的制度，以更好地理解所有这些现象。 这项工作将使用分子动力学计算机模拟进行，从分子尺度的细节，以及估计散装材料的性能可能会得到。

The liquid state is an enduring source of challenges for our understanding of matter. Even the simplest classical liquid is a dense, disordered, and strongly-interacting many-body system. Liquids thus present us with rich behavior and formidable complexity, especially at the molecular scale. Some of the most important and perplexing open questions in liquid-state physics occur in supercooled liquids. The nature of amorphous solid formation at the glass transition is a continuing source of open debate. Similarly, the nucleation of crystalline solids from the liquid state is also incompletely understood; e.g. the ability of theory to predict crystal nucleation rates with quantitative accuracy remains poor for many important systems. While many of these questions are of a fundamental nature, practical applications abound. For example, the glass-forming ability of metallic alloys is an area of active commercial interest, with new companies making amorphous metal products such as golf clubs and aircraft components. Colloidal liquids are also an area of explosive growth, to which our understanding of classical molecular liquids is directly transferrable. In the context of supercooled liquids, a number of distinct and complex phenomena converge: the thermodynamics of metastable phases; the complex transport properties of viscous liquids; and the non-equilibrium kinetics of crystal nucleation. This proposal describes a program of research to investigate the properties of supercooled liquids, with a deliberate focus on regimes in which these phenomena become intertwined, to better understand all of them. This work will be carried out using molecular dynamics computer simulations, from which both molecular-scale details, as well as estimates of bulk material properties may be obtained.