(731f) Understanding the Molecular Mechanisms Underlying the Nucleation and Growth of Metal Nanoparticles

Understanding the crystallization of metals is of key importance for many applications e.g. for metal nanoparticles and catalysts. In particular, it is crucial to control the morphology as well as the structure of the crystallites formed during the crystallization process. When and how the selection of a specific structure (or polymorph) occurs remains a long-standing issue. This is a very complex problem, resulting from a subtle interplay between thermodynamics and kinetics. Solving this issue has remained elusive so far, even on simple model systems composed of spherical particles.

In this talk, we use molecular simulations to shed light on the molecular mechanisms underlying the crystallization from liquid metals. We model the metals with a many-body embedded-atom model (EAM) potential [1,2]. The ability of the model to predict the thermodynamic properties of the bulk (including the melting temperature) was assessed in previous work. We consider here liquid metals, supercooled at temperatures 15% and 20% below the melting point, and study the crystallization process in those systems. For both degrees of supercooling, we simulate the homogeneous nucleation event and the subsequent growth of the critical nuclei. Our simulation results shed light on the molecular mechanisms underlying the structure selection process during the crystallization process.

[1] C. Desgranges and J. Delhommelle, J. Am. Chem. Soc. 129, 7012 (2007).

[2] C. Desgranges and J. Delhommelle, J. Chem. Phys. 127, 144509 (2007).