Forbidden nuclear magnetic resonance transitions between singlet and triplet states in spin-12 pair systems in rotating solids
✍ Scribed by Toshihito Nakai; Robin Challoner; Charles A. McDowell
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 539 KB
- Volume
- 180
- Category
- Article
- ISSN
- 0009-2614
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✦ Synopsis
Forbidden transitions between singlet and triplet nuclear spin states in chemically equivalent spin-l /2 pair systems were observed in the "P cross-polarization magic-angle spinning (CPMAS) nuclear magnetic resonance (NMR) spectrum of 1,2-bis(2,4,6tri-tert-butylphenyl)diphosphene (TBPDP). The fine structure of the resonance lines changed dramatically with rotor spinning frequency. Using the average Hamiltonian theory, the origin of these singular phenomena was revealed to be due to high-order anisotropic interactions in the solid state. From analysis of the spectra, the value of the Jcoupling between the chemically equivalent 3'P nuclei in TBPDP was estimated to be 577 k 15 Hz.