Department of Mechanical Engineering, Keio University, 3-14-1 Hiyoshi, Kohoku-ku, Yokohama 223-8522, Japan.
Molecules. 2021 Mar 5;26(5):1421. doi: 10.3390/molecules26051421.
In this work, the advantages of applying the temperature and pressure replica-exchange method to investigate the phase transitions and the hysteresis for liquid-crystal fluids were demonstrated. In applying this method to the commonly used Hess-Su liquid-crystal model, heat capacity peaks and points of phase co-existence were observed. The absence of a smectic phase at higher densities and a narrow range of the nematic phase were reported. The identity of the crystalline phase of this system was found to a hexagonal close-packed solid. Since the nematic-solid phase transition is strongly first order, care must be taken when using this model not to inadvertently simulate meta-stable nematic states at higher densities. In further analysis, the Weighted Histogram Analysis Method was applied to verify the precise locations of the phase transition points.
在这项工作中，展示了应用温度和压力复制交换方法研究液晶流体的相变和滞后的优势。在将该方法应用于常用的 Hess-Su 液晶模型时，观察到了热容峰和相共存点。报道了在较高密度下不存在向列相和向列相范围较窄的情况。该系统的结晶相被发现为六方密堆积固体。由于向列-固体相变强烈地属于一级相变，因此在使用该模型时必须小心，以免在较高密度下无意中模拟亚稳向列态。在进一步的分析中，应用了加权直方图分析方法来验证相变点的精确位置。
