Pretti M, Buzano C
Istituto Nazionale per la Fisica della Materia (INFM) and Dipartimento di Fisica, Politecnico di Torino, Corso Duca degli Abruzzi 24, I-10129 Torino, Italy.
J Chem Phys. 2004 Dec 15;121(23):11856-66. doi: 10.1063/1.1817924.
We investigate a lattice-fluid model of water, defined on a three-dimensional body centered cubic lattice. Model molecules possess a tetrahedral symmetry, with four equivalent bonding arms, aiming to mimic the formation of hydrogen bonds. The model is similar to the one proposed by Roberts and Debenedetti [J. Chem. Phys. 105, 658 (1996)], simplified in that no distinction between bond "donors" and "acceptors" is imposed. Bond formation depends both on orientation and local density. In the ground state, we show that two different ordered (ice) phases are allowed. At finite temperature, we analyze homogeneous phases only, working out phase diagram, response functions, the temperature of maximum density locus, and the Kauzmann line. We make use of a generalized first-order approximation on a tetrahedral cluster. In the liquid phase, the model exhibits several anomalous properties observed in real water. In the low temperature region (supercooled liquid), there are evidences of a second critical point and, for some range of parameter values, this scenario is compatible with the existence of a reentrant spinodal.
我们研究了一种水的晶格流体模型，该模型定义在三维体心立方晶格上。模型分子具有四面体对称性，有四个等效的键合臂，旨在模拟氢键的形成。该模型类似于罗伯茨和德贝内代蒂提出的模型[《化学物理杂志》105, 658 (1996)]，简化之处在于不对键的“供体”和“受体”进行区分。键的形成既取决于取向也取决于局部密度。在基态下，我们表明允许存在两种不同的有序（冰）相。在有限温度下，我们仅分析均匀相，计算相图、响应函数、最大密度轨迹温度和考兹曼线。我们在四面体簇上采用广义一阶近似。在液相中，该模型展现出在真实水中观察到的几种反常性质。在低温区域（过冷液体），有证据表明存在第二个临界点，并且对于某些参数值范围，这种情况与折返旋节线的存在是相容的。
