ORIENTATIONAL ORDERING TRANSITION IN SOLID C60
ORIENTATIONAL ORDERING TRANSITION IN SOLID C60
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DOI：
10.1103/physrevlett.66.2911
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发表时间：
1991-06-03
影响因子：
8.6
通讯作者：
COX, DE
中科院分区：
文献类型：
--
作者：
HEINEY, PA;FISCHER, JE;COX, DE
对固体 C60 的同步加速器 X 射线粉末衍射和差示扫描量热测量揭示了 249 K 时从四分子基础的低温简单立方结构到面心立方结构的一级相变。转变时的自由能变化约为 6.7 J/g。 衍射强度的模型拟合与室温下完全取向无序一致，并且与低温下取向有序的发展而不是分子位移或扭曲一致。
Synchrotron-x-ray powder-diffraction and differential-scanning-calorimetry measurements on solid C60 reveal a first-order phase transition from a low-temperature simple-cubic structure with a four-molecule basis to a face-centered-cubic structure at 249 K. The free-energy change at the transition is approximately 6.7 J/g. Model fits to the diffraction intensities are consistent with complete orientational disorder at room temperature, and with the development of orientational order rather than molecular displacements or distortions at low temperature.