几种与X射线吸收谱有关的技术

Some Special Techniques Related to XAFS

扼要介绍几种与XAFS有关的技术 .原子的XAFS(AXAFS) ,这是由吸收原子的外层价电子的散射造成的 ,主要用来研究原子外层的电子结构及近邻环境的关系 .近边结构X射线显微境 ,这是将NEXAFS与X射线显微镜相结合的成像技术 ,除了利用相同元素在近边区吸收的差异可清晰成像的技术以外 ,还可作出生物分子中各有机分子或天然元素的定量分布图 .光声X射线吸收精细结构 ,这是通过在吸收边两侧测量光声信号获得XAFS的技术 ,利用相位的延滞 ,可测得薄膜的厚度 .与其它技术联合形成综合谱 :DAFS是XRD与XAFS的综合谱 ,可研究在特定的位置上特定价态原子的近邻结构 ;XAFS还可以与X射线Raman、X射线粉末衍射、光电子能谱等技术联合用于结构研究 .

Some special techniques related to XAFS are simply introduced. Atomic XAFS is produced by the photoelectron scattering by the outer valance electrons of the absotrption atoms, which can be used for studying the outer electron structure of the absorption atoms and the relationship between election structure and the local structure. NEXAFS STXM is an image technique by the combination of BEXAFS and STXM. The image is produced by the difference of the absorption of the different matters consisted by the same elements in the range of NEXAFS. In addition, NEXAFS STXM can quantitatively map the organic and inorganic components of biological tissue. Photoacoustic XAFS is obtained by the measurements of the photoacoustic signal on the both sides of the absorption edge. The film thickness can be measured by the phase delay of the photoacaustic signal. DAFS technique is a complex of XAFS and XRD. The local structure of the atom with spcecial site and appointed valence can be determined by DAFS. Furthermore, the XAFS can be complexed with X ray Raman scattering, XRD, XPS and FTIR for structural studies, respectiuely.