Molecular simulation studies of the liquid-liquid phase transition of low temperature and high-pressure water

利用扩展系综下的Monte Carlo方法研究了水的各种性质。为了探讨低温高压条件下水的“液-液相变”和“第二临界点”存在的可能性，采用216水为研究对象，采用单原子（mW）模型，在180 K下进行了多尺度等温Monte Carlo计算.当修正MUBA权重因子时，发现在0.2GPa和0.5GPa下，体系的体积和结构发生了显著变化，这被认为是相变。由于在本系统中，在相同的压力下有几个状态具有不同的体积，我们需要找到另一种方法来表达MUBA权重因子。

Monte Carlo calculations under the extended ensemble were performed to investigate the various character of water. In order to investigate the existence possibility of the "liquid-liquid phase transition" and "second critical point" of water under low temperature and high-pressure conditions, the multibaric-isothermal Monte Carlo calculation was carried out at 180K with the 216 water by using the monatomic (mW) model. While updating the MUBA weight factor, the significant changes in volume and in structure, which are considered to be phase transitions, were found at 0.2 GPa and 0.5GPa. Since there were several states that have different volume under the same pressure in the present system, we need to find another way to express the MUBA weight factor.