中文摘要：

电子定域化函数（ELF）是研究电子结构的重要工具.本文介绍了电子定域性的概念,从电子对密度和动能密度两个角度详细讨论了ELF的物理意义与其函数形式的联系,并将ELF推广到自旋极化形式.通过实例分析,指出了参考项在ELF 中起到了关键性作用.对两种自旋极化形式的ELF 的比较发现：CheckDen 和TopMoD程序中使用的形式并不合理,明显低估了单电子区域的定域性.最后指出了一些文献由于对ELF函数的错误理解而在引用时出现的错误.

英文摘要：

The electron localization function （ELF） is an important tool to study electronic structure. In this article, the concept of electron localization is introduced and the overlap between the physical meaning and functional form of the ELF is discussed in detail from two points of view： electron pair density and kinetic energy density. Additionally, we extend the ELF to a generalized spin-polarized form. From case studies we found that the reference term plays an important role in the ELF. A comparison between the two spinpolarized forms of ELF shows that the form used in the CheckDen and TopMoD programs is unreasonable as they obviously underestimate the degree of localization in the single-electron region. Finally, we point out some mistakes in the literature because of a misunderstanding of the ELF.