Nucleation in Supercooled Liquids
This event is part of the Departmental Seminars.
Dissertation Committee: William Klein, Thomas Keyes, Harvey Gould, Rama Bansil and Kevin Black
Nucleation is the process by which the metastable phase decays into the stable phase. It is widely observed in nature, and is responsible for many phenomena like cloud formation and crystal growth. The classical theory of nucleation predicts that the objects that initiate the decay from the metastable to the stable phase are compact droplets of the stable phase. For quenches deep into the metastable phase, however, the droplets may be ramified, with a structure very different from the stable phase. This has significant implications for material properties.
I study nucleation via molecular dynamics simulation of Lennard-Jonesium, a model system for liquid-solid transformations. The system is quenched from a high temperature, where the liquid is stable, to a lower temperature, where the liquid is metastable, and allowed to nucleate via fluctuation-driven clusters referred to as critical droplets. I will present a study of the structure of the critical droplet, and my attempts to probe it using indirect methods. I will show evidence that the presence of a hitherto unstudied 'planar' structure has a significant influence on the nucleation and growth of the critical droplet.