𝔖 Bobbio Scriptorium
✦   LIBER   ✦

Longitudinal NMR relaxation of 27Al nuclei in zeolites

✍ Scribed by Jürgen Haase; Harry Pfeifer; Wolfgang Oehme; Jacek Klinowski

Publisher
Elsevier Science
Year
1988
Tongue
English
Weight
385 KB
Volume
150
Category
Article
ISSN
0009-2614

No coin nor oath required. For personal study only.

✦ Synopsis

Longitudinal relaxation times, T,, of "Al in zeolitic frameworks are between z 0.3 and 70 ms depending on temperature. The relaxation IS governed by the electric quadrupole interaction with the crystal electric field gradients modulated by translational motion of polar sorbate molecules and charge-compensating cations. Dipolar interactions with paramagnctic impurities become significant as a relaxation mechanism only at low temperatures.

📜 SIMILAR VOLUMES

27Al nutation NMR of zeolites
27Al nutation NMR of zeolites
✍ F.M.M. Geurts; A.P.M. Kentgens; W.S. Veeman 📂 Article 📅 1985 🏛 Elsevier Science 🌐 English ⚖ 367 KB

AI NhlR nulnlion experiment for qundrupolar nuclei d ~rwlopcd by Snmoson and Lippmnn has been applied 10 "Al spins in rhe zeoliw co~~lysr H-ZSM-5. The "Al numGon sprc~a change with WBE~ con~cnl in the portzs or this zcolik. rrom which ir can bc concluded thal in the hydrated SWIG many "Al nuclei arc

Measuring the Longitudinal NMR Relaxatio
Measuring the Longitudinal NMR Relaxation Rates of Fast Relaxing Nuclei Using a Signal Eliminating Relaxation Filter
✍ D.Flemming Hansen; Jens J. Led 📂 Article 📅 2001 🏛 Elsevier Science 🌐 English ⚖ 112 KB

A new experiment for selective determination of the relaxation rates of fast relaxing NMR signals is presented. The experiment is derived from the conventional inversion recovery experiment by substituting the 180 • inversion pulse of this experiment with a signal eliminating relaxation filter (SERF

27Al&{1H} cross-polarization and ultrahi
27Al&{1H} cross-polarization and ultrahigh-speed 27Al MAS NMR spectroscopy in the characterization of USY zeolites
✍ Lars Kellberg; Magnus Linsten; Hans J. Jakobsen 📂 Article 📅 1991 🏛 Elsevier Science 🌐 English ⚖ 545 KB

41 MAS NMR spectroscopy with 'H cross-polarization is shown to be an efficient technique for distinguishing non-framework from framework Al in USY zeolites and has revealed the presence of non-framework tetrahedral Al. Field-dependent measurements and simulations show that the non-framework 30 ppm 2