In situ XAFS studies of the adsorption of benzene in zeolite beta: differences between fluorescence and electron yield detection

Abstract

By using a newly designed cell to perform in-situ XAFS at the A1 K edge the adsorption of benzene in Beta zeolite is studied. The data were collected both in fluorescence and electron yield mode. The adsorption of benzene changed the near edge structure of the AI K edge in Beta-zeolite. These changes are much larger when the data are collected in the electron yield mode. A broad satellite peak has been observed in the electron yield data. This peak can be assigned to a core-hole 2-electron final state. The 2electron final state occurs since in addition to the excited electron another electron is transferred from the benzene to the 3p orbital of the AI absorber atom (charge transfer, CT). In fluorescence mode this peak is much less pronounced, because the twoelectron state decays primarily via Auger decay.