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

By using a newly designed cell to perform in-situ XAFS at the Al 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 cha nged the near edge structure of the Al K edge in Beta-zeolite. These change s 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 pe ak can be assigned to a core-hole 2-electron final state. The 2-electron fi nal state occurs since in addition to the excited electron another electron is transferred from the benzene to the 3p orbital of the Al absorber atom (charge transfer, CT). In fluorescence mode this peak is much less pronounc ed, because the two-electron state decays primarily via Auger decay.