Predicting the Phase Diagram of Two-Dimensional Colloidal Systems with Long-Range Interactions

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• 作者：Sergio J. Mej&iacute ; a-Rosales ; Alejandro Gil-Villegas ; Boris I. Ivlev ; Jaime Ruiz-Garc&iacute ; a
• 刊名：Journal of Physical Chemistry B
• 出版年：2006
• 出版时间：November 9, 2006
• 年：2006
• 卷：110
• 期：44
• 页码：22230 - 22236
• 全文大小：209K
• 年卷期：v.110,no.44(November 9, 2006)
• ISSN：1520-5207

文摘

The phase diagram of a two-dimensional model system for colloidal particles at the air-water interface wasdetermined using Monte Carlo computer simulations in the isothermic-isobaric ensemble. The micrometer-range binary colloidal interaction has been modeled by hard disklike particles interacting via a secondaryminimum followed by a weaker longer-range repulsive maximum, both of the order of k_BT. The repulsivepart of the potential drives the clustering of particles at low densities and low temperatures. Pinned voids areformed at higher densities and intermediate values of the surface pressure. The analysis of isotherms,translational and orientational correlation functions as well as structure factor gives clear evidence of thepresence of a melting first-order transition. However, the melting process can be also followed by a metastableroute through a hexatic phase at low surface pressures and low temperatures, before crystalization occurs athigher surface pressure.