Initial and Final State Effects in the Photoelectron and Auger Spectra of Si and Al Bonded in Zeolites

Abstract

The dependence of the core level binding energies, E b, of Si, Al, and O bonded in zeolites on the concentration of skeletal Al is investigated. The line shape changes of Al KLL Auger spectra appearing with decreasing concentration of Al in zeolites are described. Initial and final state effects influencing core level binding energies of zeolites are discussed on a qualitative level. Different screening of the hole states localized on Al and Si is demonstrated. Evidence is shown for the dominant influence of initial state effects on the core level E b values of Si and Al.

Ion Exchange of NH4−Ferrierite with Co2+: ESCA Study

“…However, the former effect does not influence significantly the values of α‘(Al), as in that case it would induce their decrease and not increase with increasing Δ N , which is evident for the investigated series of ferrierites (except Fer(0.82). A decrease of α‘(Al) with decreasing lattice parameter a o of zeolites has been observed in ref . Thus, the observed increase of α‘(Al) with increasing extent of ion exchange is explicable as a consequence of the lengthening of Al − O bond upon ion exchange.…”

“…The dependence of intensities of Al KLL Auger lines on the structure of zeolites has been demonstrated previously. 11 Whereas the intensity of the Al K L 2,3 L 2,3 Auger line (normalized relative to the intensity of Al 2p photoelectron line) decreases with the contraction of a 0 , the intensities of the Al K L 1 L 2,3 and Al K L 1 L 1 Auger lines increase. However, the relative intensities of all of the Al KLL Auger lines of the Co ferrierites increase with increasing ∆N.…”

“…The dependence of the intensities of Al KLL Auger lines on the structure of zeolite (that is O-Al(Si)-O bond angle and Al(Si)-O bond length, respectively) has been demonstrated in a previous article. 11 The values of R′ are related to the polarizability R of the electrons localized on the oxygen atoms of a zeolitic skeleton, and the coordination mode of a given atom. 12,13 Investigation of the photoelectron and Auger lines of zeolitic Al and ion exchanged metal cation thus might enable one to obtain unique information on the sites of metal cations in the voids of zeolites and on the strength of the interaction of Me n+ with the zeolite site.…”

“…The effects induced by ion exchange of zeolites can be investigated by X-ray photoelectron spectroscopy (XPS), − and X-ray induced Auger electron spectroscopy (XAES). − Information about the stoichiometry of ion exchange may be derived from the intensities of the photoelectron lines of pertinent cations and the Al 2p photoelectron line. It is possible to distinguish between exchanged metal cations and metal oxide precipitates through the case of metal core level binding energy ( E b ) shifts.…”

An experimental study of charge distribution in crystalline and amorphous Si nanoclusters in thin silica films

“…Figure 2 shows the Si 2p and Si KLL peaks of three as grown (A.G.) samples with different Si content showing the different chemical states present. The three extra peaks at 1610.9 eV, 1608.7 eV and 1607.8 eV in the Si KLL spectra are plasmon peaks of the Si 0 , Si + and Si 2+ states and their use optimised peak fitting 31,32 During heat treatment of the as grown samples, the suboxides thermally decomposed to SiO 2 and Si 0 nanoclusters. It is clear from Figure 3 that annealing decreased the Si 3+ -, Si 2+ -, Si + -and Si 0 -content, and increased that of Si 4+ .…”