Suppression of Sub-surface Freezing in Free-Standing Thin Films of a Coarse-grained Model of Water

Abstract

Freezing in the vicinity of water-vapor interfaces is of considerable interest to a wide range of disciplines, most notably the atmospheric sciences. In this work, we use molecular dynamics and two advanced sampling techniques, forward flux sampling and umbrella sampling, to study homogeneous nucleation of ice in free-standing thin films of supercooled water. We use a coarse-grained monoatomic model of water, known as mW, and we find that in this model a vapor-liquid interface suppresses crystallization in its vicinity. This suppression occurs in the vicinity of flat interfaces where no net Laplace pressure in induced. Our free energy calculations reveal that the pre-critical crystalline nuclei that emerge near the interface are thermodynamically less stable than those that emerge in the bulk. We investigate the origin of this instability by computing the average asphericity of nuclei that form in different regions of the film, and observe that average asphericity increases closer to the interface, which is consistent with an increase in the free energy due to increased surface-to-volume ratios.

13 pages, 10 figures

References in corpus (4)

• Forward Flux Sampling-type schemes for simulating rare events: Efficiency analysis
• Rate of Homogeneous Crystal Nucleation in molten NaCl
• Local order parameters for use in driving homogeneous ice nucleation with all-atom models of water
• The Effect of Substrate on Thermodynamic and Kinetic Anisotropies in Atomic Thin Films

Cited by in corpus (8)

• Crystal Nucleation in Liquids: Open Questions and Future Challenges in Molecular Dynamics Simulations
• The Many Faces of Heterogeneous Ice Nucleation: Interplay Between Surface Morphology and Hydrophobicity
• Molecular simulations of heterogeneous ice nucleation. I. Controlling ice nucleation through surface hydrophilicity
• Thermodynamically Driven Assemblies and Liquid-liquid Phase Separations in Biology
• Ice Formation on Kaolinite: Insights from Molecular Dynamics Simulations
• Studying Rare Events using Forward-Flux Sampling: Recent Breakthroughs and Future Outlook
• Contour forward flux sampling: Sampling rare events along multiple collective variables
• Perspective: Surface Freezing in Water: A Nexus of Experiments and Simulations