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Polarized absorption spectroscopy
Abstract:
The application of polarized absorption spectroscopy as a powerful method in the characterization of modified zeolitic molecular sieve crystals can supply information on (i) the electronic states, (ii) the alignment of zeolite-hosted colouring guests, and (iii) the concentration of the colouring species at very low loadings. The following examples are reported for modifications brought about during the synthesis: the isomorphous framework substitution (CoII in AIPO4-5), the incorporation of ions (Se2 anions in cancrinite), and the encapsulation of metal complexes (cobalticinium, [CoIII(ν5-C5H5)2]+ in nonasils). The adsorption of chromophores (p-nitrodimethylaniline in AlPO4-5) is shown as an important post-synthesis modification.