23Na and 27Al NMR Study of Structure and Dynamics in Mordenite
نویسندگان
چکیده
Temperature dependencies of 27Al and 23Na nuclear magnetic resonance spectra and spin-lattice relaxations in mordenite have been studied in static and magic angle spinning regimes. Our data show that the spin-lattice relaxations of the 23Na and 27Al nuclei are mainly governed by interaction of nuclear quadrupole moments with electric field gradients of the crystal, modulated by translational motion of water molecules in the mordenite channels. At temperatures below 200 K, the dipolar interaction of nuclear spins with paramagnetic impurities becomes an important relaxation mechanism of the 23Na and 27Al nuclei.
منابع مشابه
Dynamic effects in MAS and MQMAS NMR spectra of half-integer quadrupolar nuclei: calculations and an application to the double perovskite cryolite.
Dynamic processes such as chemical exchange or rotations between inequivalent orientations can affect the magic-angle spinning (MAS) and the multiple-quantum (MQ) MAS NMR spectra of half-integer quadrupolar nuclei. The present paper discusses such dynamic multisite MAS and MQMAS effects and applies them to study the dynamic processes that occur in the double perovskite cryolite, Na3AlF6. Dynami...
متن کاملElectronic Supplementary Information: Local Structures and Al/Si Ordering in Lanthanum Aluminosilicate Glasses Explored by Advanced Al NMR Experiments and Molecular Dynamics Simulations
1. S1. Fictive-Temperature Estimations. 2. Figure S1. MD-Derived Fictive Temperatures. 3. Figure S2. A Selection of Deconvoluted 27Al MAS NMR Spectra. 4. Figure S3. MD-derived Radial Distribution Functions. 5. Figure S4. MD-derived Bond-Angle Distributions. 6. Table S1. MD-Derived Structural Data at Different Melt-Cooling Rates. 7. Table S2. Deconvolution Results of 27Al MAS NMR Spectra Recorde...
متن کاملReaction rate uncertainties and the operation of the NeNa and MgAl chains during HBB in intermediate-mass AGB stars
Context. We test the effect of proton-capture reaction rate uncertainties on the abundances of the Ne, Na, Mg and Al isotopes processed by the NeNa and MgAl chains during hot bottom burning (HBB) in asymptotic giant branch (AGB) stars of intermediate mass between 4 and 6 M⊙ and metallicities between Z = 0.0001 and 0.02. Aims. We provide uncertainty ranges for the AGB stellar yields, for inclusi...
متن کاملThe sodium ions inside a lipophilic G-quadruplex channel as probed by solid-state (23)Na NMR.
We report solid-state 23Na NMR and X-ray crystallographic results for a self-assembled G-quadruplex channel formed by a guanine nucleoside, 5'-tert-butyl-dimethylsilyl-2',3'-O-isopropylidene guanosine (G 1). The study provides an unambiguous 23Na NMR identification for the Na+ ions inside a lipophilic G-quadruplex channel. The crystalline nature of the sample yields a remarkably high resolution...
متن کاملMas Nmr Spectroscopic Study of the Polytypes of the Titanosilicate Penkvilksite
Simulations of 29Si and 23Na MAS NMR spectra indicate the presence of differing proportions of two polytypes and a third phase in three samples of penkvilksite, Na4Ti2Si8O22•5H2O. The most abundant peaks are assigned to the 2O and 1M polytypes, and a third set of peaks are provisionally assigned to a proposed 2M polytype. The quadrupolar interaction parameters for 23Na, Cq and , were calculated...
متن کامل