A development of the system for analysing X-ray whole-powder-data without using a structural model

研制了X射线粉末衍射数据分析系统。它是基于G. S. Pawley（J.Appl.Cryst.，14，357 - 361，1981）。该方法已应用于X射线粉末衍射的数据分析。它可以进一步细化晶胞参数。分析可以在不使用结构模型的情况下进行。因此，系统用户不需要结构知识。如果样品含有内标物质，则可以在轮廓细化过程中自动校正由于仪器和样品原因引起的峰位移。在两年的研究项目中，1）设计了系统，2）建立了X射线粉末衍射数据的轮廓模型，3）用Fortran语言编写了计算机程序，4）对各种样品进行了测试，结果表明：1）与传统的轮廓拟合技术相比，该系统对重叠反射的分解具有很高的分辨率，2）整个粉型自动细化，性价比高; 3）细化参数精度高。未来的系统应在以下几个方面加以改进：1）进一步提高分析的自动化程度; 2）加强对最小二乘精化的不良条件的处理。

The system for analyzing X-ray powder diffraction data has been developed. Is is based on the procedure developed for analyzing neutron powder diffraction data by G.S.Pawley (J.Appl.Cryst.,14,357-361,1981).The procedure has been applied to the data analysis in X-ray powder diffraction.The system can decompose overlapping reflections into individual ones,and give integrated intensities and individual profile shapes as a function of diffraction angle. It can further refine unit cell parameters.The analysis can be performed without using a structural model.Thus structural knowledges are not required for system users.If the sample contains a internal standard material,the peak shift due to instrumental and specimen causes can be corrected automatically during the profile refinement.During 2 years of the research project,1) the system was designed,2)the profile model for X-ray powder diffraction data has been developed,3) the computer program was written Fortran statements,and 4)the system was tested for various samples.The system demonstrated that1)it has a high resolving power for decomposing overlapping reflections compared to the convevtional profile fitting technique,2) it has high cost-performance since the whole powder pattern is refined automatically, and 3)it can provied high accuracy in refined parameters. The future system should be improved in some respects;1) a further improvement of automation of analysis,and 2) toughening against the bad conditioning of the least squares refinement.