Oxide electronic polarizabilities and aluminum coordination at the outer surface of zeolites obtained by X-ray photoelectron spectroscopy

摘要: Abstract An extension of the simple electrostatic model Auger parameter developed a few years ago by Moretti [Surf. Interf. Anal. 16 (1990) 159; 17 (1991) 352] is presented and discussed. It shown that site-sensitive can bring very useful information about local chemical environment core-ionized atoms. In zeolites, Si Al parameters permit direct determination in-framework electronic polarizability two oxide species Si–O–Si(Al) Si–OM–Al, where M (H,Na,…) counter-cation negative charge on Al. The knowledge these quantities fundamental to theoretical investigations adsorptive properties zeolites. This approach was previously investigated Pellenq Nicholson [J. Chem. Soc. Faraday Trans. 89 (1993) 2499] who, however, due limitations model, only obtained averaged oxygen polarizability. extended also permits identification framework tetra- tri- coordinated sites in zeolites (Bronsted Lewis acid sites), as well extra-framework hexa-coordinated dealuminated We applied our all for which data were reported literature.