X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
Phys Chem Chem Phys. 2013 Jun 14;15(22):8566-72. doi: 10.1039/c3cp44347g. Epub 2013 Apr 15.
The evolution of the X-ray structure factor and corresponding pair distribution function of SiO2 has been measured upon cooling from the melt using high energy X-ray diffraction combined with aerodynamic levitation. Small changes in the position of the average Si-O bond distance and peak width are found to occur at ~1500(100) K in the region of the calorimetric glass transition temperature, T(g) and the observed density minima. At higher temperatures deviations from linear behavior are seen in the first sharp diffraction peak width, height and area at around 1750(50) K, which coincides with the reported density maximum around 1.2T(g).
采用高能 X 射线衍射结合气动悬浮技术，测量了 SiO2 的 X 射线结构因子和相应的对分布函数在熔体冷却过程中的演变。在比热玻璃化转变温度 T(g)和观察到的密度最小值区域，约 1500(100) K 时，平均 Si-O 键距离和峰宽的位置发现发生了微小变化。在较高温度下，在大约 1750(50) K 时，第一尖锐衍射峰的宽度、高度和面积出现了偏离线性行为，这与约 1.2T(g)处报道的密度最大值相吻合。
