C_(60)固体中的相变  

Phase Transition in Solid C_(60)

作　　者：徐志瑾[1] 严继民[1] 

机构地区：[1]中国科学院化学研究所,北京100080

出　　处：《物理化学学报》1995年第11期991-996,共6页Acta Physico-Chimica Sinica

基　　金：国家自然科学基金

摘　　要：本文用（exp－6－1）势对固体C60中分子间的相互作用进行计算，给出常温及常温以下固体C60中分子存在的状态.计算表明，常温下C60高速旋转，随着温度降低，旋转速度逐渐减小，并且旋转轴向也逐渐趋于单一.当降到～260K时发生一级相变，此时FCC晶胞中（0，0，0）、（1／2，1／2，0）、（0，1／2，1／2）及（1／2，0，1／2）四套格点上的分子各只绕［111］、［111］、［111］及［111］三重轴旋转，C60晶体从FCC结构变为SC结构；当温度继续下降到一定程度（～90K）时，发生二级相变，C60由晶态变为玻璃态．The interactions between C60 molecules in solid state are calculated by the potential model (exp-6-1). The states of C6o molecules in solid are given at room temperature and at lower temperature. C60 molecule rotates rapidly at room temperature; the rotation rate decreases and the rotational axes tend to ordering as temperature becomes lower. And at about 260K the structure undergoes a first-order phase transiton from the high-temperatuxe FCC phase to the ordered SC structure. The molecule equlvalence above 260K is now broken by rotating the four molecules through the same angle but around different <111> axes: the molecule at (0,0,0) around [111], that at (1/2,1/2,0)around [111], that at (0,1/2,1/2) around [111] and at (1/2,0,1/2) around [111]. At about 90K, the system undergoes a second-order phase transtion-glass transition.

关 键 词：相变 取向相变 碳60 

分 类 号：O635.1[理学—高分子化学] O631.22[理学—化学]