文章基本信息

标题：Molecular dynamics simulations of liquid silica crystallization
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作者：Haiyang Niu ; Pablo M. Piaggi ; Michele Invernizzi 等
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2018
卷号：115
期号：21
页码：5348-5352
DOI：10.1073/pnas.1803919115
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Silica is one of the most abundant minerals on Earth and is widely used in many fields. Investigating the crystallization of liquid silica by atomic simulations is of great importance to understand the crystallization mechanism; however, the high crystallization barrier and the tendency of silica to form glasses make such simulations very challenging. Here we have studied liquid silica crystallization to β-cristobalite with metadynamics, using X-ray diffraction (XRD) peak intensities as collective variables. The frequent transitions between solid and liquid of the biased runs demonstrate the highly successful use of the XRD peak intensities as collective variables, which leads to the convergence of the free-energy surface. By calculating the difference in free energy, we have estimated the melting temperature of β-cristobalite, which is in good agreement with the literature. The nucleation mechanism during the crystallization of liquid silica can be described by classical nucleation theory.
关键词：silica ; crystallization ; metadynamics ; free-energy calculations ; classical nucleation theory