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2011
ACL
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M.Deschamps, C.Roiland, B.Bureau, G.Yang, L.Le Pollès, D.Massiot, '77Se solid-state NMR investigations on AsxSe1-x glasses using CPMG acquisition under MAS', Solid State NMR 40 72-77 (2011) doi:10.1016/j.ssnmr.2011.06.001
77Se (I = 1/2) solid-state NMR is a very sensitive probe of the local structure of selenide glasses, which themselves are promising for optical applications. In this work, we show that although 77Se has a low natural abundance (7.58%) and a wide spectral range, the sensitivity can be dramatically increased by using Carr-Purcell-Meiboom-Gill (CPMG) trains of rotor-synchronized PI pulses during the detection of 77Se magnetization but may be affected by chemical shift anisotropy when the Magic Angle Spinning rate is not fast enough and by offset effects. The indirect dimension of the T2CPMG-resolved spectrum shows a strong influence of the J-couplings between naturally occurring 77Se pairs. The resulting spectra show that the structural model known as "chains crossing model" is not entirely suitable to describe the glassy network of the Se-rich compositions.
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