Librational tunneling levels of NH, + ions in an (NH,),SnBr, single crystal were determined by studying the proton Zeeman relaxation. The relaxation rate speeds up when any of the tunnel frequencies vI equals n va (n = f , 1, 2). where v0 is the proton resonance frequency. The energy separation betw
Proton double quantum coherence and cross-relaxation in (NH4)2SnBr6
✍ Scribed by M. Punkkinen; A. Kaikkonen; E.E. Ylinen; M. Kankaanpää; A.H. Vuorimäki
- Publisher
- Elsevier Science
- Year
- 1998
- Tongue
- English
- Weight
- 146 KB
- Volume
- 13
- Category
- Article
- ISSN
- 0926-2040
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✦ Synopsis
A proton double quantum coherence signal can be observed exclusively from the T species NH4 groups (with the total spin I = 1) in ammonium compounds at low temperatures by the three-pulse sequence 90x degrees - tpr - 90x degrees - tev - 90x degrees - ta, where tpr and ta are of the magnitude of the inverse line width and tev very short. The usefulness of this pulse sequence, preceded by the additional pulse sequence 90x degrees - t1 -90(-x) degrees - t2 for creating an unbalance between the A and T species magnetizations, was demonstrated by applying it to cross-relaxation studies in (NH4)2SnBr6.
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