理论上对二级相变中热容、体膨胀系数、等温压缩系数三个热力学物理量的变化进行了分析,进而使用自旋链模型的基态能量和von Neumann熵随模型参数变化的突变行为对二级相变中这三个物理量的变化所引起的系统序变进行模拟,得到二级相变中热容、体膨胀系数、等温压缩系数的变化是由于系统内部微观上发生关联序变的结果。

The changes of the three thermodynamic physical quantities such as thermal capacity,volume expansion,and isothermal compressibility in the second order phase transformation are analyzed in theory.The change of the system order with changes of the three thermodynamic physical quantities caused in the second order phase transformation is simulated by means of the discontinuity behavior that the ground state energy and von Neumann of the model of spin chain change along with the change of the parameter of the model. The conclusion is that the change of the related order of the interior of the system leads to the change of thermal capacity,volume expansion,and isothermal compressibility in the second order phase transformation.