采用Rietveld精修方法解析粉末晶体MgF_2、SrF_2的原子热振动

Analysis of atomic thermal vibration by rietvled method in powder MgF_2and SrF_2

分别在室温(25℃)和高温(300℃)下,通过X射线衍射实验对Mg F2和Sr F2晶体进行了晶体结构的检测.利用基于Rietveld精修方法的RIETAN-2000程序对所得实验结果进行了解析,精修了Mg F2和Sr F2晶体在不同温度下的各晶体结构参数,获得了原子各向同性温度因子B.通过Maximum Entropy Method(MEM)解析得到了Mg F2和Sr F2晶体的等高电子密度分布图谱,实现了电子密度分布的可视化.

In this paper,the crystal structures of Mg F2 and Sr F2 were tested by X- ray diffraction( XRD) at room temperature( 25℃) and high temperature( 300℃),respectively. The crystal structure parameters were refined and the temperature factor B was obtained with Rietvled method which was carried out in the RIETAN-2000 program. In addition,the XRD results were analyzed with Maximum Entropy Method( MEM) method and the electron density distributions were shown clearly in the form of equal pitch contour,which realized the visualization of the distribution of electron density.