Dudalov D E, Tsiok E N, Fomin Yu D, Ryzhov V N
Institute for High Pressure Physics RAS, 142190 Kaluzhskoe shosse, 14, Troitsk, Moscow, Russia.
J Chem Phys. 2014 Nov 14;141(18):18C522. doi: 10.1063/1.4896825.
In the present paper, using a molecular dynamics simulation, we study a nature of melting of a two-dimensional (2D) system of classical particles interacting through a purely repulsive isotropic core-softened potential which is used for the qualitative description of the anomalous behavior of water and some other liquids. We show that the melting scenario drastically depends on the potential softness and changes with increasing the width of the smooth repulsive shoulder. While at small width of the repulsive shoulder the melting transition exhibits what appears to be weakly first-order behavior, at larger values of the width a reentrant-melting transition occurs upon compression for not too high pressures, and in the low density part of the 2D phase diagram melting is a continuous two-stage transition, with an intermediate hexatic phase in accordance with the Kosterlitz-Thouless-Halperin-Nelson-Young scenario. On the other hand, at high density part of the phase diagram one first-order transition takes place. These results may be useful for the qualitative understanding the behavior of water confined between two hydrophobic plates.
在本文中，我们使用分子动力学模拟研究了一个二维经典粒子系统的熔化性质，该系统通过纯排斥各向同性核软化势相互作用，此势用于定性描述水和其他一些液体的反常行为。我们表明，熔化情形极大地取决于势的软度，并随光滑排斥肩宽度的增加而变化。当排斥肩宽度较小时，熔化转变呈现出似乎是弱一级行为；而当宽度较大时，在不太高压的压缩过程中会发生再入熔化转变，并且在二维相图的低密度部分，熔化是一个连续的两阶段转变，按照科斯特利茨 - Thouless - 哈珀林 - 尼尔森 - 杨的情形，存在一个中间的六方相。另一方面，在相图的高密度部分会发生一次一级转变。这些结果可能有助于定性理解限制在两个疏水板之间的水的行为。
