Bugaev Lusegen A, Bokhoven Jeroen A van, Khrapko Valerii V, Avakyan Leon A, Latokha Jana V
Department of Physics, Southern Federal University, Zorge str., 5, 344090 Russia
ETH Zurich, Institute for Chemical and Bioengineering, ETH Zurich, HCI E127, 8093 Zurich, Switzerland.
J Phys Chem B. 2009 Apr 9;113(14):4614-8. doi: 10.1021/jp8098285.
Experimental Si K edge X-ray absorption near-edge fine structure (XANES) of zeolite faujasite, mordenite, and beta are interpreted by means of the FEFF8 code, replacing the theoretical atomic background mu(0) by a background that was extracted from an experimental spectrum. To some extent, this diminished the effect of the inaccuracy introduced by the MT potential and accounted for the intrinsic loss of photoelectrons. The agreement of the theoretical and experimental spectra at energies above the white lines enabled us to identify structural distortion around silicon, which occurs with increasing aluminum content. The Si K edge XANES spectra are very sensitive to slight distortions in the silicon coordination. Placing an aluminum atom on a nearest neighboring T site causes a distortion in the silicon tetrahedron, shortening one of the silicon-oxygen bonds relative to the other three.
通过FEFF8代码对八面沸石、丝光沸石和β沸石的实验Si K边X射线吸收近边精细结构（XANES）进行了解释，用从实验光谱中提取的背景取代了理论原子背景μ(0)。在一定程度上，这减少了MT势引入的不准确性的影响，并考虑了光电子的固有损失。白线以上能量处理论光谱与实验光谱的一致性使我们能够识别硅周围的结构畸变，这种畸变随着铝含量的增加而发生。Si K边XANES光谱对硅配位中的轻微畸变非常敏感。在最近邻的T位上放置一个铝原子会导致硅四面体发生畸变，使其中一个硅氧键相对于其他三个键缩短。
