K_3C_(60)晶体中钾离子的平衡位置

Equilibrium Positions of Potassium Cation in K_3C_(60) Crystal

分析八面体空隙中心碱金属的相互作用势能，研究碱金属沿[111]、[110]和[100]三个不同方向移动时，势能的变化情况，结果表明，对于K3C60晶体，K+离子在三个不同方向上都存在非中心平衡位置，而且在三个不同方向上，非中心平衡位置相对中心的偏移量不同，在[111]轴上为0.98■，在［110］轴方向上为0.78■,[100]方向上为0．56■,在[111]轴方向的非中心的势能是最小值，为-508．59meV通过对计算结果的分析，认为非中心平衡位置的出现应归因于短程相互作用，其中与C60的相互作用是最主要的，其势能最低点对应的位置不在中心；三个不同方向的非中心平衡位置偏离中心距离不同，是因为与之对应晶面上的C60面密度不同．

By analyzing the potefitial of an octahedral alboi cation, the varying of the potentialof alkali cation, whose position is in three different directions of [111], [110] and [100] was calculated.The results show that off-center sites in K3C60 crystal actually ealst in these three directions. The deviations from the center are different to be 0.98 , 0.78 , 0.56 respectively in [111], [110] and [100] directions. The potential at off-center site in [111] direction is the lowest, -508.59meV. The existence of officenter sites owes to the short range interaction of alkali, especially the interaction between alkali and C60 anions. The most important is that the site corresponding to the lowest potential point is not at the symmetric center. The reason of the different deviations in these three directions is the different densities of C60 anion in the corresponding crystal planes.