Optical spectroscopy on Se clusters and chains confined in zeolites
Centre de Recherche sur la Matiére Divisée (CRMD), UMR 6619 CNRS, Université d’Orléans, 1bis rue de la Férollerie, 45071, Orléans Cedex 2, France
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The incorporation of selenium into the supercages of zeolite Y leads to the formation of Se 8 rings and distorted Se chains in a ratio which is influenced by the nature of the zeolitic cations. Here we review Raman (including resonance Raman) and UV/vis absorption spectroscopy results on Se encapsulated into a number of cation-exchanged faujasite zeolites. Both rings and chains give rise to characteristic Raman bands. In particular, low-frequency Raman bands are attributed to localized vibrations in ordered segments of distorted chains. The UV/vis absorption spectra indicate an opening of the band gap of selenium upon confinement in these zeolites. This can be reversed through electronic interaction with zeolite cations.
© EDP Sciences, Società Italiana di Fisica, and Springer-Verlag, 2003