用重整化群理论研究胶体模型体系的相行为

Investigation of the Phase Behaviour for Colloidal Model Systems by Renormaliz ation-Group Theory

用Yukawa势能函数表达胶体颗粒之间的吸引作用 .用Duh Mier Y Teran状态方程表达液相Helmholtz自由能 .用一阶微扰理论、固体硬球径向分布函数解析式和改进的胞腔模型建立固相状态方程 .结合建立的状态方程和重整化群(RenormalizationGroup ,RG)理论 ,研究了胶体模型体系的液 -液相平衡和液 -固相平衡 .研究表明 ,颗粒之间色散作用量程参数的变化对胶体模型体系的相行为有重要影响 .

The Yukawa potential was used for the attractive interaction of colloidal particles. The Duh-Mier-Y-Teran's equation of state (EOS) was used to express the Helmholtz free energy for the fluid phase. The first-order perturbation theory, the analytical expression of the radial distribution function (RDF) for the hard sphere potential in the FCC-crystal structure and the modified cell model were combined to establish the EOS for the solid phase. By using the established EOS and the renormalization-group (RG) theory, the fluid-fluid and fluid-solid equilibria for colloidal model systems were studied. Investigation shows that the attractive range parameter plays an important role in the phase transition of colloidal model systems. The obtained results agree well with the simulation data.