Pressure dependence of crystal growth mechanism

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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.