碱金属低掺杂C_(60)化合物中碱金属离子平衡位置的研究

THE EQUILIBRIUM SITES OF ALKALI CATIONS IN LIGHT ALKALI-DOPED C_60)

以Na2RbC60为例,在分析了现有模型的局限性后,考虑C60分子的取向,重新构造了碱金属离子与C60之间相互作用模型,并由此研究了碱金属离子在C60晶体中的平衡位置,确定了八面体位置的离子偏离中心,四面体位置的离子保留在中心.结果更符合实验事实.同时指出,由于取向有序,晶体内位于不同坐标的八面体间隙离子与四面体间隙离子体现出明显的两类.

By the analysis of limitations of the model proposed by Goze \%et al.\%the equilibrium sites of alkali cations in Na\-2RbC\-\{60\} have been investigated using the potential model consisting of short\|range interatomic (ionic) potentials and long\|range Coulomb interaction.It is shown that the cations in the octahedral coordination shift away from the center of the octahedral sites,while those in the tetrahedral coordination remain in the central positions.The result also shows the octahedral sites,as well as the tetrahedral sites,are not all equivalent and can be divided into two distinct sets in orientationally ordered phase.