Ankudinov A L, Nesvizhskii A I, Rehr J J
Dept. of Physics, University of Washington, Seattle 98195-1560, USA.
J Synchrotron Radiat. 2001 Mar 1;8(Pt 2):92-5. doi: 10.1107/s0909049500016435.
The interpretation of X-ray absorption spectra in terms of electronic structure has long been of interest. Hole counts derived from such spectra are often interpreted in terms of free-atom occupation numbers or Mülliken counts. It is shown here, however, that renormalized-atom (RA) and cellular counts are better choices to characterize the configuration of occupied electron states in molecules and condensed matter. A projection-operator approach is introduced to subtract delocalized states and to determine quantitatively such hole counts from X-ray absorption spectra. The described approach is based on multiple-scattering theory (MST) and on atomic calculations of a smooth transformation relating the X-ray absorption spectra to local projected densities of states (LDOS). Theoretical tests for the s and d electrons in transition metals show that the approach works well.
长期以来，根据电子结构对X射线吸收光谱进行解释一直备受关注。从这类光谱得出的空穴数通常根据自由原子占据数或穆利肯数来解释。然而，本文表明，重整化原子（RA）计数和元胞计数是表征分子和凝聚态物质中占据电子态构型的更好选择。引入了一种投影算符方法来减去离域态，并从X射线吸收光谱中定量确定此类空穴数。所描述的方法基于多重散射理论（MST）以及将X射线吸收光谱与局域投影态密度（LDOS）联系起来的平滑变换的原子计算。对过渡金属中s电子和d电子的理论测试表明该方法效果良好。
