Kinetic control of competing nuclei in a dimer lattice-gas model

• Published in: arXiv.org
• Main Authors: Mandal, Dipanjan, Quigley, David
• Format: Paper Journal Article
• Language: English
• Published: Ithaca Cornell University Library, arXiv.org 03.01.2023
• Subjects: Crystallites; Dimers; Metastable phases; Molecular structure; Nucleation; Nuclei; Physics - Soft Condensed Matter; Physics - Statistical Mechanics
• ISSN: 2331-8422
• DOI: 10.48550/arxiv.2208.06403

Nucleation is a key step in the synthesis of new material from solution. Well-established lattice-gas models can be used to gain insight into the basic physics of nucleation pathways involving a single nucleus type. In many situations a solution is supersaturated with respect to more than one precipitating phase. This can generate a population both stable and metastable nuclei on similar timescales and hence complex nucleation pathways involving competition between the two. In this study we introduce a lattice-gas model based on two types of interacting dimer representing particles in solution. Each type of dimer nucleates to a specific space-filling structure. Our model is tuned such that stable and metastable phases nucleate on a similar timescale. Either structure may nucleate first, with probability sensitive to dimer mobility. We calculate these nucleation rates via Forward-Flux Sampling and demonstrate how the resulting data can be used to infer the nucleation outcome and pathway. Possibilities include direct nucleation of the stable phase, domination of long-lived metastable crystallites, and pathways in which the stable phase nucleates only after multiple post-critical nuclei of the metastable phase have appeared.