Se- Se -Se

1. Study of Chalcogenide Glasses via Solid-State NMRGregory S. Boebinger, Florida State University, DMR 0654118 NMR Facility Se-Se-Se Heavy (high-Z) nuclei such as selenides and tellurides in chalcogenide glasses tend to exhibit large chemical shift anisotropy (CSA), which diminishes NMR site resolution at high magnetic fields even with very fast magic angle spinning (MAS). A solid-state NMR technique called “magic-angle turning phase-adjusted sideband separation”, or MATPASS, was developed to separate the anisotropic and isotropic chemical shift in two dimensions. The separation allows for site resolution and measurement of CSA to characterize the electronic and bonding environment of nuclei. The incorporation of CPMG multiple-echo acquisition (a standard NMR pulse sequence) provides a 10-fold sensitivity enhancement for the application of MATPASS to chalcogenide glasses. Ge-Se-Ge GeSe4 glass: (a) Typical 77Se MAS (νr = 10 kHz) NMR spectrum at B0 = 19.6 T. (b) Isotropic NMR projection obtained from the 2D spectrum in (c), where spinning sidebands due to CSA are individually separated in two dimensions. Citation: MATPASS/CPMG: A sensitivity enhanced magic-angle spinning sideband separation experiment for disordered solids, Ivan Hung, Trenton Edwards, Sabyasachi Sen, Zhehong Gan, Journal of Magnetic Resonance, 221, 103-109 (2012).