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.
Received: 1 January 2003, Published online: 14 October 2003PACS:
78.30.-j Infrared and Raman spectra - 82.75.Mj Measurements and simulation of properties (optical, structural) of molecules in zeolites