Development of ab-initio software for interpretation of electronic spectra

许多不同种类的电子能谱已被用于新材料的研究和开发。然而，这项技术的充分利用的瓶颈在于缺乏良好的理论工具来解释实验光谱。这两种方法对解释近边X射线吸收精细结构和近边电子能量损失都很有用。其中一个是相对论多电子程序，可以重现三维过渡金属化合物的金属-L边缘谱。系统地研究发现，该程序适用于大多数过渡金属氧化物。另一个是能带结构程序，用于计算核心空穴与激发电子之间的关联。计算结果很好地再现了许多化合物的实验光谱。

Many different kinds of electron spectroscopy have been used for research and development of new materials. However, the bottleneck of full utilization of such technique is composed of the lack of good theoretical tools to interpret the experimental spectra.In the present study, we have developed two kinds of software. Both of them are very useful for interpretation of NEXAFS (near edge X-ray absorption fine structures) and ELNES (electron energy loss near edge structures).One is a relativistic multi-electron program that can reproduce metal-L_<23> edge spectra of 3d transition metal compounds. We made systematic investigation to find that the program can be useful for most of transition metal oxides.The other is a band structure program to be used to compute correlation between core holes and an excited electron.Experimental spectra of many compounds are well reproduced by the calculation.