Pressure dependence of crystal growth mechanism

利用光学液体高压池，对二甲苯和间二甲苯二元体系的成核过程与压力、温度和浓度的关系进行了研究。推导出的界面张力随着压力的增加和对二甲苯含量的降低而增加。界面张力随温度的升高而降低。研制了一种新型的高压测样仪。用该仪器对对二甲苯的液态和固态状态方程进行了部分测定。利用液-固相变的体积变化和本研究中测量的其它物理量推导出溶解能量变化的压力和温度依赖性，并利用上述物理量考察了界面张力与压力依赖性的机理，给出了下图。压力的依赖性来自于两者的断裂键能的增加，压缩和压缩的界面过剩熵的减少。

The pressure, temperature, and concentration dependence of nucleation was observed with the p-and m-xylene binary system using an optical liquid high pressure cell. The deduced interfacial tension increased with increasing pressure and with decreasing p-xylene content. The interfacial tension decreased with increasing temperature.The new instrument detecting the volume of sample at high pressure was developed. With the instrument, the equations of state of p-xylene both in liquid and solid state were measured partially. The pressure and temperature dependence of the energy change of dissolution was deduced with the volume change of the liquid to solid phase transition and the other thermodynamical quantities measured in this study.The mechanism giving the pressure dependence to the interfacial tension was examined with the above mentioned thermodynamical quantities, which gives the following figure. The pressure dependence arises from both the increase of breaking bond energy by compression and the decrease of the interfacial excess entropy by compression.