Díaz-Herrera Enrique, Ramírez-Santiago Guillermo, Moreno-Razo José A
Departamento de Física, Universidad Autónoma Metropolitana-Iztapalapa, Apartado Postal 55-534, México 09340, DF, Mexico.
Phys Rev E Stat Nonlin Soft Matter Phys. 2003 Dec;68(6 Pt 1):061204. doi: 10.1103/PhysRevE.68.061204. Epub 2003 Dec 24.
We have carried out extensive equilibrium molecular dynamics simulations to investigate the liquid-vapor coexistence in partially miscible binary and ternary mixtures of Lennard-Jones fluids. We have studied in detail the time evolution of the density profiles and the interfacial properties in a temperature region of the phase diagram where the condensed phase is demixed. The composition of the mixtures is fixed, 50% for the binary mixture and 33.33% for the ternary mixture. The results of the simulations clearly indicate that in the range of temperatures 78<T<102 K-in the scale of argon-the system evolves towards a metastable alternated liquid-liquid lamellar state in coexistence with its vapor phase. These states can be achieved if the initial configuration is fully disordered-that is, when the particles of the fluids are randomly placed on the sites of an fcc crystal or the system is completely mixed. As temperature decreases these states become very well defined and more stables in time. We find that below 90 K, the alternated liquid-liquid lamellar state remains alive for 80 ns, in the scale of argon, the longest simulation we have carried out. Nonetheless, we believe that in this temperature region these states will be alive for even much longer times.
我们进行了广泛的平衡分子动力学模拟，以研究 Lennard-Jones 流体的部分互溶二元和三元混合物中的液-气共存。我们详细研究了相图中凝聚相发生分层的温度区域内密度分布和界面性质的时间演化。混合物的组成是固定的，二元混合物为 50%，三元混合物为 33.33%。模拟结果清楚地表明，在 78<T<102 K（以氩气为尺度）的温度范围内，系统朝着与其气相共存的亚稳交替液-液层状状态演化。如果初始构型完全无序，即流体粒子随机放置在面心立方晶体的格点上或系统完全混合，就可以达到这些状态。随着温度降低，这些状态变得非常明确且在时间上更稳定。我们发现，在低于 90 K 时，在氩气尺度下，交替液-液层状状态在我们进行的最长 80 ns 模拟中仍然存在。尽管如此我们相信，在这个温度区域，这些状态将存活更长时间。
