Greaves G N, Durham P J, Diakun G, Quinn P
Nature. 1981 Nov 12;294(5837):139-142. doi: 10.1038/294139a0.
The measurement of X-ray absorption fine structure of metals- both in the extended region (EXAFS) as well as in the near edge region (XANES)-has been widely discussed (see refs 1-6 for Cu and refs 7-9 for Mn). The recent availability of intense X-ray fluxes from storage rings has usually been exploited for EXAFS leaving the XANES often with poorer resolution than earlier work performed on conventional sources (for example, compare the near edge structure for copper in ref. 1 with refs 3 or 6). In addition, whilst the theory and analysis of EXAFS is relatively well-established, a theory for the strong scattering regime near to the absorption edge has only recently been developed. We report here the first high resolution XANES spectra for Cu and Mn which were performed at the SRS storage ring at Daresbury. Although both metals have close-packed structures consisting of atoms of similar size their local atomic structure is different in detail. Significant differences are found in their respective XANES reflecting the senstivity of this region of the X-ray absorption fine structure to the local atomic structure. Spectra for the two metals have been analysed using the new multiple scattering formalism. This is a real space calculation and unlike a conventional band structure approach it does not require structural periodicity but works from the local arrangement of atoms.
金属的X射线吸收精细结构测量——包括扩展区（EXAFS）和近边区（XANES）——已得到广泛讨论（关于铜的文献见参考文献1 - 6，关于锰的文献见参考文献7 - 9）。近期储存环产生的强X射线通量通常用于EXAFS测量，导致XANES的分辨率往往比早期使用传统光源的工作更差（例如，比较参考文献1中铜的近边结构与参考文献3或6）。此外，虽然EXAFS的理论和分析相对成熟，但吸收边附近强散射区域的理论直到最近才得以发展。我们在此报告首次在达累斯伯里的SRS储存环上获得的铜和锰的高分辨率XANES光谱。尽管这两种金属都具有由大小相近的原子组成的密堆积结构，但其局部原子结构在细节上有所不同。在它们各自的XANES中发现了显著差异，这反映了X射线吸收精细结构的这一区域对局部原子结构的敏感性。已使用新的多重散射形式对这两种金属的光谱进行了分析。这是一种实空间计算，与传统的能带结构方法不同，它不需要结构周期性，而是基于原子的局部排列进行计算。
