Characterization of macroscopic disorder in a porous glass with NMR microimaging and scanning electron microscopy
Article Abstract:
Intensity fluctuations in one-dimensional NMR microimaging profiles of imbibed porous Pyrex glass filters have been studied with the goal of characterizing macroscopic disorder in a porous glass. An approach for characterizing some aspects of the macroscopic randomness from the NMR microimaging profiles of the medium has been developed. The intensity-intensity correlation functions of the one-dimensional NMR profiles are interrelated, as a function of length scale involving the dimensions of the porous network and the embedding space, and the dimensions in the projection. Scanning electron microscopy was successfully used for corroboration. Statistical properties of distributions of peak separations for intensity fluctuations do tell something about pore size and distances between pores in such media.
Publication Name: Canadian Journal of Chemistry
Subject: Chemistry
ISSN: 0008-4042
Year: 1998
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A solid state 31P NMR study of the synthesis of phosphorus sulfides from PCl3 and H2S in microporous materials
Article Abstract:
Synthesis of phosphorus sulfides from H2S and PCl3 in microporous materials has been studied using solid state 31P NMR. Reaction and interaction of PCl3 and PCl3-H2S mixtures with ALPO-5, Silicalite and NaX, NaA and NaY have been investigated. The goal was to produce phosophorus sulfide clusters in the pores. Inside the NaY alpha-cages P4S3, P4S7, alpha-P4S5, and beta-P4S6 were found. A new species, possibly another geometric isomer of P4S4 with C3v symmetry was found. Using 129Xe NMR, it was found that Xe was kept out of the micropores by the phosphorus sulfides. Sulfides lower than P4S7 are small enough to quickly undergo pseudo-isotropic reorientation in the NaY alpha-cage. The regular array of identical molecules hoped for did not result, but information gained may be useful in achieving that end.
Publication Name: Canadian Journal of Chemistry
Subject: Chemistry
ISSN: 0008-4042
Year: 1998
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