熔融Rb2ZnCl4的分子动力学模拟研究

采用在RbCl模拟和ZnCl₂模拟中选用的两体有效势，进行了晶态和熔融态Rb₂ZnCl₄的分子动力学模拟.模拟给出了Rb₂ZnCl₄ 6种径向分布函数，Zn-Cl和Rb-Cl间径向分布函数与新近的广延X射线吸收精细结构实验结果很好相符.在模拟产生的瞬态构型基础上进行了键序参数分析，研究了晶态和熔融态中的局部结构.模拟结果表明，Zn原子与其近邻Cl原子构成相当稳定的正四面体结构，并且熔融Rb_关键词：

MOLECULAR DYNAMICS STUDY ON THE STRUCTURES OF MOLTEN Rb2ZnCl4

The structures of molten and crystalline states of Rb₂ZnCl₄ have been simulated by molecular dynamics with the effective potentials which had been applied in the simulations of RbCl and ZnCl₂ systems.Six radial distribution functions (RDF) simulated are presented,of which Zn-Cl and Rb-Cl RDFs are in good accordance with the recent EXAFS experimental results.Based on the instantaneous configurations given by the simulations,the local structures in molten and crystalline states have been studied with bond-order parameter method.The results show that the Zn atom and its neighboring Cl atoms form a stable tetrahedral structure,and the Zn/Cl tetrahedral structures in molten Rb₂ZnCl₄ are stabler than those in molten ZnCl₂.The presence of a good quantity of stable (ZnCl₄)^2- units without apparent network-like structures is the typical characteristics of the molten Rb₂ZnCl₄.The simulations for crystalline state did not describe the complex coordinations between Rb and Cl atoms in detail,which showed that the two-body effective potentials are not enough to simulate the behaviors of Rb atoms in the crystalline Rb₂ZnCl₄.