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，由于缺乏良好的理论工具来解释实验光谱，这一技术的充分利用成为瓶颈。这两个程序对解释NEXAFS（near edge X-ray absorption fine structures）和ELNES（electron energy loss near edge structures）都是非常有用的：一个是相对论多电子程序，可以再现<23>3d过渡金属化合物的金属-L_ edge谱;我们进行了系统的研究，发现该程序对大多数过渡金属氧化物都是有用的，另一个是用于计算核心空穴与激发电子之间关联的能带结构程序，计算结果与许多化合物的实验光谱吻合得很好。

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.