Effect of aluminum on the local structure of silicon in zeolites as studied by Si K edge X-ray absorption near-edge fine structure: spectra simulation with a non-muffin tin atomic background.
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.
Bugaev
Lusegen A
LA
Department of Physics, Southern Federal University, Zorge str., 5, 344090 Russia
Bokhoven
Jeroen A van
JA
ETH Zurich, Institute for Chemical and Bioengineering, ETH Zurich, HCI E127, 8093 Zurich, Switzerland.
Khrapko
Valerii V
VV
Department of Physics, Southern Federal University, Zorge str., 5, 344090 Russia
Avakyan
Leon A
LA
Department of Physics, Southern Federal University, Zorge str., 5, 344090 Russia
Latokha
Jana V
JV
Department of Physics, Southern Federal University, Zorge str., 5, 344090 Russia
D000535:Aluminum / Q000737:chemistry*; D015394:Molecular Structure; D012825:Silicon / Q000737:chemistry*; D013052:Spectrometry, X-Ray Emission / Q000379:methods; D017641:Zeolites / Q000737:chemistry*
D017641:Zeolites; D000535:Aluminum; D012825:Silicon